document_title: Liquid fuel

question_text: what are the properties of an ideal combustible fuel

text: Liquid fuel

text: General properties[edit]

text: Some common properties of liquid fuels are that they are easy to transport, and can be handled with relative ease. Also they are relatively easy to use for all engineering applications, and home use. (Fuels like Kerosene are rationed and available in government subsidized shops in India for home use.) Liquid fuels are also used most popularly in Internal combustion engines.

text: Some very technically important properties include: flash point, fire point, cloud point, and pour point.

text: Petroleums[edit]

text: Most liquid fuels used currently are produced from petroleum. The most notable of these is gasoline. Scientists generally accept that petroleum formed from the fossilized remains of dead plants and animals by exposure to heat and pressure in the Earth's crust.

text: Gasoline[edit]

text: Gasoline is the most widely used liquid fuel. Gasoline, as it is known in United States and Canada, or petrol virtually everywhere else, is made of hydrocarbon molecules (compounds that contain hydrogen and carbon only) forming aliphatic compounds, or chains of carbons with hydrogen atoms attached. However, many aromatic compounds (carbon chains forming rings) such as benzene are found naturally in gasoline and cause the health risks associated with prolonged exposure to the fuel.

text: Production of gasoline is achieved by distillation of crude oil. The desirable liquid is separated from the crude oil in refineries. Crude oil is extracted from the ground in several processes, the most commonly seen may be beam pumps. To create gasoline, petroleum must first be removed from crude oil.

text: Liquid gasoline itself is not actually burned, but its fumes ignite, causing the remaining liquid to evaporate and then burn. Gasoline is extremely volatile and easily combusts, making any leakage potentially extremely dangerous. Gasoline sold in most countries carries a published octane rating. The octane number is an empirical measure of the resistance of gasoline to combusting prematurely, known as knocking. The higher the octane rating, the more resistant the fuel is to autoignition under high pressures, which allows for a higher compression ratio. Engines with a higher compression ratio, commonly used in race cars and high-performance regular-production automobiles, can produce more power; however, such engines require a higher octane fuel. Increasing the octane rating has, in the past, been achieved by adding 'anti-knock' additives such as lead-tetra-ethyl. Because of the environmental impact of lead additives, the octane rating is increased today by refining out the impurities that cause knocking.

text: Diesel[edit]

text: Conventional diesel is similar to gasoline in that it is a mixture of aliphatic hydrocarbons extracted from petroleum. Diesel may cost more or less than gasoline, but generally costs less to produce because the extraction processes used are simpler. Some countries (particularly Canada and India) also have lower tax rates on diesel fuels.

text: After distillation, the diesel fraction is normally processed to reduce the amount of sulfur in the fuel. Sulphur causes corrosion in vehicles, acid rain and higher emissions of soot from the tail pipe (exhaust pipe). Historically, in Europe lower sulfur levels than in the United States were legally required. However, recent US legislation reduced the maximum sulphur content of diesel from 3,000 ppm to 500 ppm in 2007, and 15 ppm by 2010. Similar changes are also underway in Canada, Australia, New Zealand and several Asian countries. See also Ultra-low-sulfur diesel.

text: A diesel engine is a type of internal combustion engine which ignites fuel by injecting it into a combustion chamber previously compressed with air (which in turn raises the temperature) as opposed to using an outside ignition source, such as a spark plug.

text: Kerosene[edit]

text: Kerosene is used in kerosene lamps and as a fuel for cooking, heating, and small engines. It displaced whale oil for lighting use. Jet fuel for jet engines is made in several grades (Avtur, Jet A, Jet A-1, Jet B, JP-4, JP-5, JP-7 or JP-8) that are kerosene-type mixtures. One form of the fuel known as RP-1 is burned with liquid oxygen as rocket fuel. These fuel grade kerosenes meet specifications for smoke points and freeze points.

text: In the mid-20th century, kerosene or "TVO" (Tractor Vaporising Oil) was used as a cheap fuel for tractors. The engine would start on gasoline, then switch over to kerosene once the engine warmed up. A "heat valve" on the manifold would route the exhaust gases around the intake pipe, heating the kerosene to the point where it can be ignited by an electric spark.

text: Kerosene is sometimes used as an additive in diesel fuel to prevent gelling or waxing in cold temperatures. However, this is not advisable in some recent vehicle diesel engines, as doing so may interfere with the engine's emissions regulation equipment.

text: Natural gas and liquefied petroleum gas[edit]

text: Compressed natural gas[edit]

text: Natural gas, composed chiefly of methane, can be compressed to a liquid and used as a substitute for other traditional liquid fuels. Its combustion is very clean compared to other hydrocarbon fuels, but the fuel's low boiling point requires the fuel to be kept at high pressures to keep it in the liquid state. Though it has a much lower flash point than fuels such as gasoline, it is in many ways safer due to its higher autoignition temperature and its low density, which causes it to dissipate when released in air.

text: Liquefied petroleum gas (LPG)[edit]

text: LP gas is a mixture of propane and butane, both of which are easily compressible gases under standard atmospheric conditions. It offers many of the advantages of compressed natural gas (CNG), but does not burn as cleanly, is denser than air and is much more easily compressed. Commonly used for cooking and space heating, LP gas and compressed propane are seeing increased use in motorized vehicles; propane is the third most commonly used motor fuel globally.

text: Non-petroleum fossil fuels[edit]

text: When petroleum is not easily available, chemical processes such as the Fischer-Tropsch process can be used to produce liquid fuels from coal or natural gas. Synthetic fuels from coal were strategically important during World War II for the German military. Today synthetic fuels produced from natural gas are manufactured, to take advantage of the higher value of liquid fuels in transportation.

text: Biodiesel[edit]

text: Biodiesel is similar to diesel, but has differences akin to those between petrol and ethanol. For instance, biodiesel has a higher cetane rating (45-60 compared to 45-50 for crude-oil-derived diesel) and it acts as a cleaning agent to get rid of dirt and deposits. It has been argued that it only becomes economically feasible above oil prices of $80 (£40 or €60 as of late February, 2007) per barrel. This does however depend on locality, economic situation, government stance on biodiesel and a host of other factors- and it has been proven to be viable at much lower costs in some countries. Also, it yields about 10% less energy than ordinary diesel. Analogous to the use of higher compression ratios used for engines burning higher octane alcohols and petrol in spark-ignition engines, taking advantage of biodiesel's high cetane rating can potentially overcome the energy deficit compared to ordinary Number 2 diesel.

text: Alcohols[edit]

text: Generally, the term alcohol refers to ethanol, the first organic chemical produced by humans,[1] but any alcohol can be burned as a fuel. Ethanol and methanol are the most common, being sufficiently inexpensive to be useful.

text: Methanol[edit]

text: Methanol is the lightest and simplest alcohol, produced from the natural gas component methane. Its application is limited primarily due to its toxicity (similar to gasoline), but also due to its high corrosivity and miscibility with water. Small amounts are used in some gasolines to increase the octane rating. Methanol-based fuels are used in some race cars and model airplanes.

text: Methanol is also called methyl alcohol or wood alcohol, the latter because it was formerly produced from the distillation of wood. It is also known by the name methyl hydrate.

text: Ethanol[edit]

text: Ethanol, also known as grain alcohol or ethyl alcohol, is commonly found in alcoholic beverages. However, it may also be used as a fuel, most often in combination with gasoline. For the most part, it is used in a 9:1 ratio of gasoline to ethanol to reduce the negative environmental effects of gasoline.[citation needed]

text: There is increasing interest in the use of a blend of 85% fuel ethanol blended with 15% gasoline. This fuel blend called E85, has a higher fuel octane than most premium gasolines. When used in a modern Flexible fuel vehicle, it delivers more performance to the gasoline it replaces at the expense of higher fuel consumption due to ethanol's lesser specific energy content.[2]

text: Ethanol for use in gasoline and industrial purposes may be considered a fossil fuel because it is often synthesized from the petroleum product ethylene, which is cheaper than production from fermentation of grains or sugarcane.

text: Butanol[edit]

text: Butanol is an alcohol which can be used as a fuel in most gasoline internal combustion engines without engine modification. It is typically a product of the fermentation of biomass by the bacterium Clostridium acetobutylicum (also known as the Weizmann organism). This process was first delineated by Chaim Weizmann in 1916 for the production of acetone from starch for making cordite, a smokeless gunpowder.

text: The advantages of butanol are its high octane rating (over 100) and high energy content, only about 10% lower than gasoline, and subsequently about 50% more energy-dense than ethanol, 100% more so than methanol. Butanol's only major disadvantages are its high flashpoint (35 °C or 95 °F), toxicity (note that toxicity levels exist but are not precisely confirmed), and the fact that the fermentation process for renewable butanol emits a foul odour. The Weizmann organism can only tolerate butanol levels up to 2% or so, compared to 14% for ethanol and yeast. Making butanol from oil produces no such odour, but the limited supply and environmental impact of oil usage defeats the purpose of alternative fuels. The cost of butanol is about $1.25–$1.32 per kilogram ($0.57-$0.58 per pound or $4 approx. per US gallon). Butanol is much more expensive than ethanol (approx. $.40 per liter or 1.50 per gallon) and methanol.

text: On June 20, 2006, DuPont and BP announced that they were converting an existing ethanol plant to produce 9 million gallons (34 000 cubic meters) of butanol per year from sugar beets. DuPont stated a goal of being competitive with oil at $30–$40 per barrel ($0.19-$0.25 per liter) without subsidies, so the price gap with ethanol is narrowing.

text: Hydrogen[edit]

text: This section needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (March 2008) (Learn how and when to remove this template message)

text: Liquefied hydrogen is the liquid state of the element hydrogen. It is a common liquid rocket fuel for rocket applications and can be used as a fuel in an internal combustion engine or fuel cell. Various concept hydrogen vehicles have been lower volumetric energy, the hydrogen volumes needed for combustion are large. Hydrogen was liquefied for the first time by James Dewar in 1898.

text: Ammonia[edit]

text: Ammonia (NH3) has been used as a fuel before at times when gasoline is unavailable (e.g. for buses in Belgium during WWII). It has a volumetric energy density of 17 Megajoules per liter (compared to 10 for hydrogen, 18 for methanol, 21 for dimethyl ether and 34 for gasoline). It must be compressed or cooled to be a liquid fuel, although it does not require cryogenic cooling as hydrogen does to be liquefied.[3]


document_title: UEI College

question_text: how much does it cost to go to uei college

root

text: UEI College

text: Accreditation[edit]

text: UEI Colleges in Huntington Park, Anaheim, Chula Vista, El Monte, Encino, Ontario, San Marcos, Stockton, and Morrow are accredited through the Accrediting Council for Continuing Education and Training (ACCET). The Bakersfield, Gardena, Fresno and Riverside locations are accredited by the Accrediting Commission of Career Schools and Colleges (ACCSC), which is a national accrediting organization in the United States that provides accreditation to "postsecondary, non-degree-granting institutions and degree-granting institutions that are predominantly organized to educate students for occupational, trade and technical careers." UEI-Houston and UEI-Phoenix were formerly accredited by the Accrediting Council for Independent Colleges and Schools (ACICS), which was de-recognized by the United States Department of Education.[1]

tag: p

text: Controversy[edit]

text: UEI College has been under scrutiny for misrepresenting job placement rates, hiring unqualified teachers, and failing to fulfill promises of helping with job placement.

text: Former UEI College criminal justice instructor Paul Scazillo wrote to Senator Tom Harkin detailing the issues he saw at UEI College:[2]

text:
"UEI Admission Representatives sold these students the criminal justice program knowing most of them could never get a job in this field."
"The real problem I saw was that there was no one in Career Services working on getting these students jobs during my tenure. ... If they complain, UEI gets them security guard positions, which could have been obtained without spending thousands of dollars on a UEI certificate."
"...UEI knows full well that most of the students will not be able to get positions in any CJ field."

tag: ul

text: In 2012, the Accrediting Commission of the Accrediting Council for Continuing Education & Training (ACCET) prohibited certain UEI College campuses from enrolling new students due to the low job placement rates of graduates.[3]

text: In 2011, the Huntington Park Medical Assistant had a 33.87% job placement rate. The program had 815 graduates eligible for job placement, but only 276 were able to find employment. The following year the job placement rate was 25%. The program had 144 graduates eligible for job placement and only 36 graduates were able to find employment.

text: UEI College has been placed on probation numerous times by the Accrediting Commission of Career Schools and Colleges (ACCSC) for failing to comply with accreditation standards.[4]

text: Lawsuits

text: Cordova, et al. v. United Education Institute, et al.

text: Claimants sued United Education Institute and IEC Corporation ("UEI"), alleging that UEI used deceptive practices and misrepresentations in its in-person admissions process. Claimants alleged UEI misrepresented to prospective students that graduates of UEI would be in “high-demand” by employers, and misrepresented to prospective students the job placement rate of UEI graduates.  The case settled for $9,000,000 in 2016.

text: Tuition[edit]

text: $19,500 for an 8-9 month program.

text: (The average cost of one year of community college in California is $1,104 for residents.[5] In Georgia, the average cost is $2,378 per year for residents attending community colleges.[6])

text: Financial aid information[edit]

text: UEI College's Federal School Code is 017169.[7]

text: Tuition and fees average $13,665 and the net price average is $23,240.

text: The amount for tuition and fees apply to full-time first-time degree/certificate-seeking students. Net price average is the average yearly price charged to full-time, first-time undergraduate students receiving student aid after deducting any grant and scholarship aid. It provides an idea of how much a first-time, full-time undergraduate student who receives grant/scholarship aid pays to attend an institution after subtracting the aid.

text: Locations[edit]

text:
Anaheim, California
Bakersfield, California
Chula Vista, California
Gardena, California, formerly in Cerritos
El Monte, California
Encino, California
Fresno, California
Huntington Park, California
Ontario, California
Riverside, California
San Bernardino, California
 San Diego, California
San Marcos, California
Stockton, California
Morrow, Georgia
Jacksonville, Florida
Houston, Texas

text: Programs[edit]

text:
Automotive Technician
Business Management, Associates of Applied Science
Business Office Administration
Computer Systems Technician
Criminal Justice
Criminal Security Administration
Dental Assistant
Medical Assistant
Medical Billing and Insurance Coding
Pharmacy Technician
Vocational Nursing


document_title: Venice, Los Angeles

question_text: how far is santa monica from venice ca

question_tokens: how far is santa monica from venice ca

text: Venice, Los Angeles

text: History[edit]

text: 19th century[edit]

text: In 1839, a region called La Ballona that included the southern parts of Venice, was granted by the Mexican government to Machados and Talamantes, giving them title to Rancho La Ballona.[2][3][4] Later this became part of Port Ballona.

text: Founding[edit]

text: Venice, originally called "Venice of America," was founded by tobacco millionaire Abbot Kinney in 1905 as a beach resort town, 14 miles (23 km) west of Los Angeles. He and his partner Francis Ryan had bought two miles (3.24 km) of oceanfront property south of Santa Monica in 1891. They built a resort town on the north end of the property, called Ocean Park, which was soon annexed to Santa Monica. After Ryan died, Kinney and his new partners continued building south of Navy Street. After the partnership dissolved in 1904, Kinney, who had won the marshy land on the south end of the property in a coin flip with his former partners, began to build a seaside resort like the namesake Italian city.[5]:8

text: When Venice of America opened on July 4, 1905, Kinney had dug several miles of canals to drain the marshes for his residential area, built a 1,200-foot (370 m)-long pleasure pier with an auditorium, ship restaurant, and dance hall, constructed a hot salt-water plunge, and built a block-long arcaded business street with Venetian architecture. Tourists, mostly arriving on the "Red Cars" of the Pacific Electric Railway from Los Angeles and Santa Monica, then rode the Venice Miniature Railway and gondolas to tour the town. The biggest attraction was Venice's mile-long gently sloping beach. Cottages and housekeeping tents were available for rent.[citation needed]

text: The population (3,119 residents in 1910) soon exceeded 10,000; the town drew 50,000 to 150,000 tourists on weekends.[citation needed]

text: Amusement pier[edit]

text: Attractions on the Kinney Pier became more amusement-oriented by 1910, when a Venice Miniature Railway, Aquarium, Virginia Reel, Whip, Racing Derby, and other rides and game booths were added. Since the business district was allotted only three one-block-long streets, and the City Hall was more than a mile away, other competing business districts developed. Unfortunately, this created a fractious political climate. Kinney, however, governed with an iron hand and kept things in check. When he died in November 1920, Venice became harder to govern. With the amusement pier burning six weeks later in December 1920, and Prohibition (which had begun the previous January), the town's tax revenue was severely affected.[citation needed]

text: The Kinney family rebuilt their amusement pier quickly to compete with Ocean Park's Pickering Pleasure Pier and the new Sunset Pier. When it opened it had two roller coasters, a new Racing Derby, a Noah's Ark, a Mill Chutes, and many other rides. By 1925 with the addition of a third coaster, a tall Dragon Slide, Fun House, and Flying Circus aerial ride, it was the finest amusement pier on the West Coast. Several hundred thousand tourists visited on weekends. In 1923 Charles Lick built the Lick Pier at Navy Street in Venice, adjacent to the Ocean Park Pier at Pier Avenue in Ocean Park. Another pier was planned for Venice in 1925 at Leona Street (now Washington Street).[citation needed]

text: For the amusement of the public, Kinney hired aviators to do aerial stunts over the beach. One of them, movie aviator and Venice airport owner B. H. DeLay, implemented the first lighted airport in the United States on DeLay Field (previously known as Ince Field). He also initiated the first aerial police in the nation, after a marine rescue attempt was thwarted. DeLay also performed many of the world's first aerial stunts for motion pictures in Venice.[citation needed]

text: Politics[edit]

text: By 1925, Venice's politics had become unmanageable. Its roads, water and sewage systems badly needed repair and expansion to keep up with its growing population. When it was proposed that Venice be annexed to Los Angeles, the board of trustees voted to hold an election. Annexation was approved in the election in November 1925, and Venice was formally annexed to Los Angeles in 1926.[5]:8

text: Los Angeles had annexed the Disneyland of its day and proceeded to remake Venice in its own image. It was felt that the town needed more streets—not canals—and most of them were paved in 1929 after a three-year court battle led by canal residents. They[discuss] wanted to close Venice's three amusement piers but had to wait until the first of the tidelands leases expired in 1946.[citation needed]

text: Oil[edit]

text: In 1929, oil was discovered south of Washington Street on the Venice Peninsula. Within two years, 450 oil wells covered the area, and drilling waste clogged the remaining waterways. It was a short-lived boom that provided needed income to the community, which suffered during the Great Depression. The wells produced oil into the 1970s.[citation needed]

text: Neglect[edit]

text: Los Angeles had neglected Venice so long that, by the 1950s, it had become the "Slum by the Sea." With the exception of new police and fire stations in 1930, the city spent little on improvements after annexation. The city did not pave Trolleyway (Pacific Avenue) until 1954 when county and state funds became available. Low rents for run-down bungalows attracted predominantly European immigrants (including a substantial number of Holocaust survivors) and young counterculture artists, poets, and writers. The Beat Generation hung out at the Gas House on Ocean Front Walk and at Venice West Cafe on Dudley. Police raids were frequent during that era.[6]

text: Past Gang activity[edit]

text: The Venice Shoreline Crips and the Latino Venice 13 (V-13) were the two main gangs active in Venice. V13 dates back to the 1950s, while the Shoreline Crips were founded in the early 1970s, making them one of the first Crip sets in Los Angeles.[citation needed] In the early 1990s V-13 and the Shoreline Crips were involved in a bloody, brutal war over crack cocaine sales territories.[7]

text: By 2002, numbers of gang members in Venice were reduced due to gentrification and increased police presence. According to a Los Angeles City Beat article, by 2003, many Los Angeles Westside gang members resettled in the city of Inglewood.[8]

text: Geography[edit]

text: According to the Mapping L.A. project of the Los Angeles Times, Venice is adjoined on the northwest by Santa Monica, on the northeast by Mar Vista, on the southeast by Culver City, Del Rey and Marina Del Rey, on the south by Ballona Creek and on the west by the Pacific Ocean.[9]

text: Venice is bounded on the northwest by the Santa Monica city line. The northern apex of the Venice neighborhood is at Walgrove Avenue and Rose Avenue abutting the Santa Monica Airport. On the east the boundary runs north-south on Walgrove Avenue to the neighborhood's eastern apex at Zanja Street, thus including the Penmar Golf Course but excluding Venice High School. The boundary runs on Lincoln Boulevard to Admiralty Way, excluding all of Marina del Rey, south to Ballona Creek.[10][11]

text: The City of Los Angeles official zoning map ZIMAS shows Venice High School as included in Venice,[12] as does Google Maps.[13]

text: Cityscape[edit]

text: Venice Canal Historic District[edit]

text:
A canal

Another canal

Promotional flyer c. 1920

text: Abbot Kinney Boulevard[edit]

text: Abbott Kinney Boulevard is a principal attraction, with stores, restaurants, bars and art galleries lining the street. The street was described as "a derelict strip of rundown beach cottages and empty brick industrial buildings called West Washington Boulevard,"[14] and in the late 1980s community groups and property owners pushed for renaming a portion of the street to honor Abbot Kinney.[15][16] The renaming was widely considered as a marketing strategy to commercialize the area and bring new high-end businesses to the area.[17][18]

text: Venice Farmers Market[edit]

text: Founded in 1987, the Farmers Market operates every Friday from 7 to 11 a.m. on Venice Boulevard at Venice Way.[19]

text: 72 Market Street Oyster Bar and Grill[edit]

text: 72 Market Street Oyster Bar and Grill was one of several historical footnotes associated with Market Street in Venice, one of the first streets designated for commerce when the city was founded in 1905. During the depression era, Upton Sinclair had an office there when he was running for governor, and the same historic building where the restaurant was located was also the site of the first Ace/Venice Gallery in the early 1970s[20] and, before that, the studio of American installation artist Robert Irwin.[citation needed]

text: Historic post office[edit]

text: The Venice Post Office, a red-tile-roofed 1939 Works Progress Administration building designed by Louis A. Simon[21] on Windward Circle, featured one of two remaining murals painted in 1941 by Modernist artist Edward Biberman. Developer Abbot Kinney is in the center[22] surrounded by beachgoers in old-fashioned bathing suits, men in overalls, and a wooden roller coaster representing the Venice Pier on one side with contrasting industrial oil derricks that were once ubiquitous in the area on the other side.[23] Senior curator of American Art at Los Angeles County Museum of Art (LACMA), Ilene Susan Fort, said this is one of the better New Deal murals both artistically and historically. Although it contains brightly colored elements with amusing details, the intrusion of the ominous oil rigs and wells was very relevant at the time.[24]

text: After the post office closed in 2012, movie producer Joel Silver unveiled plans for revamping the building as the new headquarters of his company, Silver Pictures.[25] The sale included the stipulation that he, or any future owner, preserve the New Deal-era murals and allow public access.[26] Restoration of the nearly pristine mural took over a year and cost about $100,000. LACMA highlighted the mural with an exhibit that displayed additional Biberman artworks, rare historical documents and Venice ephemera with the restored mural. Silver has a long-term lease on the mural that is still owned by the US Postal Service.[24] As of June 2016, the building remains under halted construction, with completion subject to resolution of multiple property liens. The mural's whereabouts are unknown,[27] putting the lessee in violation of the lease agreement's public access requirement.[citation needed]

text: Residences and streets[edit]

text: Many of Venice's houses have their principal entries from pedestrian-only streets and have house numbers on these footpaths. (Automobile access is by alleys in the rear.) The inland walk streets are made up primarily of around 620 single-family homes.[28] Like much of the rest of Los Angeles, however, Venice is known for traffic congestion. It lies 2 miles (3.2 km) away from the nearest freeway, and its unusually dense network of narrow streets was not planned for modern traffic. Mindful of the tourist nature of much of the district's vehicle traffic, its residents have successfully fought numerous attempts to extend the Marina Freeway (SR 90) into southern Venice.[citation needed]

text: Venice Beach[edit]

text: Venice Beach, which receives millions of visitors a year, has been labeled as "a cultural hub known for its eccentricities" as well as a "global tourist destination."[29][30] It includes the promenade that runs parallel to the beach (also the "Ocean Front Walk" or just "the boardwalk"), Muscle Beach, the handball courts, the paddle tennis courts, Skate Dancing plaza, the numerous beach volleyball courts, the bike trail and the businesses on Ocean Front Walk.[citation needed]

text: The basketball courts in Venice are renowned across the country for their high level of streetball; numerous professional basketball players developed their games or have been recruited on these courts.[31]

text: Many Zapotec-speaking people from the town of Tlacolula de Matamoros, Mexico work in stalls along the boardwalk.[32]

text: Venice Beach will host skateboarding and 3x3 basketball during the 2028 Summer Olympics.[33]

text: Fishing pier[edit]

text: Along the southern portion of the beach, at the end of Washington Boulevard, is the 'Venice Fishing Pier'. A 1,310-foot (400 m) concrete structure, it first opened in 1964, was closed in 1983 due to El Niño storm damage, and re-opened in the mid-1990s. On December 21, 2005, the pier again suffered damage when waves from a large northern swell caused part of it to fall into the ocean.[citation needed] The pier remained closed until May 25, 2006, when it was re-opened after an engineering study concluded that it was structurally sound.[citation needed]

text: Breakwater[edit]

text: The Venice Breakwater is an acclaimed local surf spot in Venice. It is located north of the Venice Pier and lifeguard headquarters and south of the Santa Monica Pier. This spot is sheltered on the north by an artificial barrier, the breakwater, consisting of an extending sand bar, piping, and large rocks at its end.[citation needed]

text: In late 2010, the Los Angeles County Board of Supervisors conducted a $1.6 million replacement of 30,000 cubic yards of sand at Venice Beach eroded by rainstorms in recent years. Although Venice Beach is located in the city of Los Angeles, the county is responsible for maintaining the beach under an agreement reached between the two governments in 1975.[34]

text: Oakwood[edit]

text: The Oakwood portion of Venice, also known as "Ghost Town" and the "Oakwood Pentagon," lies inland from the tourist areas and is one of the few historically African American areas in West Los Angeles; Latinos now constitute the overwhelming majority of the residents. During the age of restrictive covenants that enforced racial segregation, Oakwood was set aside as a settlement area for Black Americans, who came by the hundreds to Venice to work in the oil fields during the 1930s and 1940s. After the construction of the San Diego Freeway, which passed through predominantly Mexican American and immigrant communities, those groups moved further west and into Oakwood where black residents were already established. White-Americans (most notably actor and filmmaker Dennis Hopper) moved into Oakwood during the 1980s and 1990s and Latinos moved out.[35]

text: By the end of the 20th century, gentrification had altered Oakwood. Although still a primarily Latino and African-American neighborhood, the neighborhood is in flux. According to Los Angeles City Beat,[36] "In Venice, the transformation is... obvious. Homes are fetching sometimes more than $1 million, and homies are being displaced every day." In 2012, the Los Angeles Times reported the prediction that the wine shops, cafes, restaurants and other businesses opening on Rose Avenue—adjacent to Oakwood—would soon lead to the other streets of Venice being transformed into upmarket areas.[35] Xinachtli, a Latino student group from Venice High School and subset of MEChA, refers to Oakwood as one of the last beachside communities of color in California. Chicanos, Hispanics, and Latinos of any race or ethnicity make up over 50% of Venice High School's student body.[37]

text: East Venice[edit]

text: East Venice is a racially and ethnically mixed residential neighborhood of Venice that is separated from Oakwood and Milwood (the area south of Oakwood) by Lincoln Boulevard, extending east to the border with the Mar Vista neighborhood, near Venice High School and Santa Monica Municipal Airport. Aside from the commercial strip on Lincoln (including the Venice Boys and Girls Club and the Venice United Methodist Church), the area almost entirely consists of small homes and apartments as well as Penmar Park and (bordering Santa Monica) Penmar Golf Course. The existing population (primarily composed of Caucasians, Hispanics/Latinos, and Asians, with small numbers of other groups) is being supplemented by new arrivals who have moved in with gentrification.[citation needed]

text: A housing project, Lincoln Place Apartment Homes, built by the Housing Authority of the City of Los Angeles is currently undergoing a $140 million renovation to add 99 new market-rate apartment homes and to update the remaining 696 existing homes. A new pool, two-story fitness center, resident park and sustainable landscaping are being added.[38] Aimco, which acquired the property in 2003, had previously been in a legal battle to determine whether or not Lincoln Place could be demolished and rebuilt. In 2010, Aimco settled with tenants and agreed to reopen the project and return scores of evicted residents to their homes and add hundreds of units to the Venice area.[39]

text: Demographics[edit]

text: The 2000 U.S. census counted 37,705 residents in the 3.17-square-mile Venice neighborhood—an average of 11,891 people per square mile, about the norm for Los Angeles; in 2008, the city estimated that the population had increased to 40,885. The median age for residents was 35, considered the average for Los Angeles; the percentages of residents aged 19 through 49 were among the county's highest.[10]

text: The ethnic breakdown was whites, 64.2%; Latinos, 21.7%; blacks, 5.4%; Asians, 4.1%, and others, 4.6%. Mexico (38.4%) and the United Kingdom (8.5%) were the most common places of birth for the 22.3% of the residents who were born abroad—considered a low figure for Los Angeles.[10]

text: The median yearly household income in 2008 dollars was $67,647, a high figure for Los Angeles. The percentage of households earning $125,000 was considered high for the city. The average household size of 1.9 people was low for both the city and the county. Renters occupied 68.8% of the housing stock and house- or apartment owners held 31.2%.[10] Property values have been increasing lately due to the presence of technology companies such as Google Inc. (which in 2011 began leasing 100,000 square feet of space in Venice) and Snap Inc. (which leases property on Market Street and Abbot Kinney).[40]

text: The percentages of never-married men (51.3%), never-married women (40.6%), divorced men (11.3%) and divorced women (15.9%) were among the county's highest. The percentage of veterans who had served during the Vietnam War was among the county's highest.[10]

text: Arts and culture[edit]

text: Venice is known as a hangout for the creative and the artistic.[41] In the 1950s and 1960s, Venice became a center for the Beat generation. There was an explosion of poetry and art. Major participants included Stuart Perkoff, John Thomas, Frank T. Rios, Tony Scibella, Lawrence Lipton, John Haag, Saul White, Robert Farrington, Philomene Long, and Tom Sewell.[6]

text: This section is in a list format that may be better presented using prose. You can help by converting this section to prose, if appropriate. Editing help is available. (May 2017)

tag: table

text: Other notable Venice poets[42] of the 20th and 21st century are Millicent Borges Accardi, Linda Albertano, Richard Beban, Molly Bendall, Terry Blackhawk, Kate Braverman, Susie Bright, Derrick Brown, Charles Bukowski, Luis Campos, Exene Cervenka, Neeli Cherkovski, Jeanette Clough, Wanda Coleman, Catherine Daly, Fred Dewey, Robert Duncan, Bob Flanagan, Amy Gerstler, S.A. Griffin, Bob Kaufman, Gluefish Lou, Bill Margolis, Ellyn Maybe, Rod McKuen, Viggo Mortensen, Holly Prado, Jack Skelley, Patti Smith, Arnold Springer, David St. John, Amber Tamblyn, Elizabeth Treadwell, David Trinidad, and Tom Waits.[citation needed]

text: Architecture[edit]

text: Designers Charles and Ray Eames had their offices at the Bay Cities Garage on Abbot Kinney Boulevard from 1943 on, when it was still part of Washington Boulevard; Eames products were also manufactured there until the 1950s.[43] The brick building's interior was redesigned by Frank Israel in 1990 as a creative workspace, opening up the interior and creating sightlines all the way through the building.[44]

text: Originally located at the Venice home of Pritzker Prize–winning architect and SCI-Arc founder Thom Mayne, the Architecture Gallery was in existence for just ten weeks in 1979 and featured new work by then-emerging architects Frank Gehry, Eric Owen Moss, and Morphosis.[45] Constructed on a long, narrow lot in 1981, the Indiana Avenue Houses/Arnoldi Triplex was designed Frank Gehry in partnership with artists Laddie Dill and Charles Arnoldi.[44] Frank Gehry has designed several well-known houses in Venice, including the Jane Spiller House (completed 1979) and the Norton House (completed 1984) on Venice Beach.[46] In 1994, sculptor Robert Graham designed a fortress-like art studio and residence for himself and his wife, actress Anjelica Huston, on Windward Avenue.[47]

text: Art[edit]

text: In the 1970s, prominent performance artist Chris Burden created some of his early, groundbreaking work in Venice, such as Trans-fixed.[48] Other notable artists who maintained studios in the area include Charles Arnoldi, Jean-Michel Basquiat,[49] John Baldessari, Larry Bell, Billy Al Bengston, James Georgopoulos, Dennis Hopper, and Ed Ruscha.[50] Organized by the Hammer Museum over the course of one weekend in 2012,[51] the open-air Venice Beach Biennial (in reference to the Venice Biennale in Italy) brought together 87 artists, including site-specific projects by established artists like Evan Holloway, Barbara Kruger as well as boardwalk veteran Arthure Moore.[52] In the 1980s and 1990s Venice Beach became a mecca for street performing turning it into a tourist attraction that rivaled many of southern California's other destinations. Chainsaw jugglers, acrobats and comics like Michael Colyar could be seen on a daily basis. Many performers like the Jim Rose Circus got their start on the boardwalk.[citation needed]

text: Music[edit]

text: Venice was where legendary rock band The Doors were formed in 1965 by UCLA alums and Venice bohemians Ray Manzarek and Jim Morrison. The Doors would go on to be inducted into the Rock and Roll Hall of Fame and are considered one of the greatest rock groups of all time, with Morrison being considered one of the greatest rock frontmen. Venice would also be the birthplace of another legendary rock band in the 1980s in Jane's Addiction. Perry Farrell, frontman and founder of Lollapalooza, was a longtime Venice resident until 2010.[53][54]

text: Venice in the 1980s also had a large number of bands playing music known as crossover thrash, a hardcore punk/thrash metal musical hybrid. The most notable of these bands is Suicidal Tendencies. Other Venice bands such as Beowülf, No Mercy, and Excel were also featured on the rare compilation album Welcome to Venice.[citation needed]

text: Parks and recreation[edit]

text: This section needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (November 2016) (Learn how and when to remove this template message)

text: The Venice Beach Recreation Center comprises a number of facilities[55] sprawling between Ocean Front Walk and the bike path, Horizon Ave to the north, and N.Venice Blvd to the south. The installation has basketball courts (unlighted/outdoor), several children play areas with a gymnastics apparatus, handball courts (unlighted), paddle tennis courts (unlighted), and volleyball courts (unlighted). At the south end of the area is the noted muscle beach outdoor gymnasium. In March 2009, the city opened a sophisticated $2,000,000 skate park on the sand towards the north. While not technically part of the park, the Graffiti Walls are on the beach side of the bike path in the same vicinity.

text: The Oakwood Recreation Center is located at 767 California Avenue. The center, which also acts as a Los Angeles Police Department stop-in center, includes an auditorium, an unlighted baseball diamond, lighted indoor basketball courts, unlighted outdoor basketball courts, a children's play area, a community room, a lighted American football field, an indoor gymnasium without weights, picnic tables, and an unlighted soccer field.[56]

text: The Westminster Off-Leash Dog Park is in Venice.[57]

text: Government[edit]

text: Venice is a neighborhood in the city of Los Angeles represented by District 11 on the Los Angeles City Council. City services are provided by the city of Los Angeles. There is a Venice Neighborhood Council that advises the LA City Council on local issues.

text: County, state, and federal representation[edit]

text: The Los Angeles County Department of Health Services SPA 5 West Area Health Office serves Venice.[58]

text: The United States Postal Service operates the Venice Post Office at 1601 Main Street and the Venice Carrier Annex at 313 Grand Boulevard.[59][60]

text: Education[edit]

text: Forty-nine percent of Venice residents aged 25 and older had earned a four-year degree by 2000, a high figure for both the city and the county. The percentages of residents of that age with a bachelor's degree or a master's degree was considered high for the county.[10]

text: Schools[edit]

text: The schools within Venice are as follows:[61]

text:
Broadway Elementary School, LAUSD, 1015 Lincoln Boulevard
Animo Venice Charter High School, 820 Broadway Street, which opened in August 2002 with 145 students, adding a freshman class of 140 every year until 2006, when it reached its full capacity of approximately 525 students. The school moved in 2006 to the former Ninety-Eighth Street Elementary School campus, which had been occupied by the Renaissance Academy.
Venice Skills Center, LAUSD, 611 Fifth Avenue
First Lutheran School of Venice, private, 815 Venice Boulevard
Westminster Avenue Elementary School, LAUSD, 1010 Abbot Kinney Boulevard
St. Mark School, private elementary, 912 Coeur d'Alene Avenue
Coeur d'Alene Avenue Elementary School, LAUSD, 810 Coeur d'Alene Avenue
Westside Leadership Magnet School, LAUSD alternative, 104 Anchorage Street

text: Venice High School serves the community.

text: Infrastructure[edit]

text: Public libraries[edit]

text: The Los Angeles Public Library operates the Venice–Abbot Kinney Memorial Branch.[62]

text: Fire department[edit]

text: The Los Angeles Fire Department operates Station 63, which serves Venice with two engines, a truck, and an ALS rescue ambulance.

text: Police[edit]

text: The Los Angeles Police Department serves the area through the Pacific Community Police Station as well as a beach sub-station.[63]

text: Los Angeles County Lifeguards[edit]

text: Venice Beach is the headquarters of the Los Angeles County Lifeguards of the Los Angeles County Fire Department. It is located at 2300 Ocean Front Walk. It is the nation's largest ocean lifeguard organization with over 200 full-time and 700 part-time or seasonal lifeguards. The headquarters building used to be the City of Los Angeles Lifeguard Headquarters until Los Angeles City and Santa Monica Lifeguards were merged into the County in 1975.

text: The Los Angeles County Lifeguards safeguard 31 miles (50 km) of beach and 70 miles (110 km) of coastline, from San Pedro in the south, to Malibu in the north. Lifeguards also provide paramedic and rescue boat services to Catalina Island, with operations out of Avalon and the Isthmus.

text: Lifeguard Division employs 120 full-time and 600 seasonal lifeguards, operating out of three sectional headquarters, Hermosa, Santa Monica, and Zuma beach. Each of these headquarters staffs a 24-hour EMT-D response unit and are part of the 911 system. In addition to providing for beach safety, Los Angeles County Lifeguards have specialized training for Baywatch rescue boat operations, underwater rescue and recovery, swiftwater rescue, cliff rescue, marine mammal rescue and marine firefighting.

text: Notable people[edit]

text:
Jay Adams, professional skateboarder
J.C. Barthel, Venice postmaster and commissioner of supplies, 1920s, president of Chamber of Commerce[64]
Charles Benefiel, artist
Charles Winchester Breedlove, Los Angeles City Council member, 1933–45, supported legalized tango games[65]
Brun Campbell, folk ragtime musician
Emilia Clarke, actress
John J. Coit, builder and operator of Venice Miniature Railway
Zach De La Rocha, musician.
Sky Ferreira, singer-songwriter, model, actress
Hulk Hogan, professional wrestler
Lennon Sisters, singers
John Lovell, businessman, member of Los Angeles Common Council[66]
Ian McShane, actor[67]
Anna Paquin, actress[68]
James Edwin Richards, crime activist and citizen journalist, editor and publisher[69]
Ronda Rousey, mixed martial artist, judoka and actress[70]
Karl L. Rundberg, Los Angeles City Council member (1957–65), opposed Venice beatniks[71]
Joanie Sommers, singer[citation needed]

text: In popular culture[edit]

text: This section needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (June 2015) (Learn how and when to remove this template message)

text: Dozens of movies and hundreds of television shows and even video games have used locations in Venice, including the beach, pleasure piers, canals and colonnades, boardwalk, schools, and restaurants.[72]

text: Some locations include the following:

text:
1914: Kid Auto Races at Venice (Charlie Chaplin—first appearance of the "Little Tramp" character)
1920: Number, Please? (Harold Lloyd)[73]
1921: The High Sign (Buster Keaton)[74]
1923: The Balloonatic (Buster Keaton)[75]
1927: Sugar Daddies (Laurel and Hardy)
1928: The Circus (Charlie Chaplin)
1928: The Cameraman (Buster Keaton)[76]
1958: Touch of Evil (Orson Welles) — shot entirely in Venice except for one indoor scene, selected by Welles as a stand-in for a fictional run-down Mexican border town.
1961: Night Tide (Dennis Hopper, Linda Lawson, written and directed by Curtis Harrington)—Shot entirely in Venice and shows the deteriorated nature of the area in the 1950s.
1971: Dracula vs. Frankenstein
1972: One Pair of Eyes - Reyner Banham loved Los Angeles — architectural critic Reyner Banham explores Los Angeles in 1972.[77]
1976: The Witch Who Came from the Sea (Millie Perkins, directed by Matt Cimber)
1979: Roller Boogie (Linda Blair, directed by Mark L. Lester)
1988: Colors
1991: The Doors (Val Kilmer, directed by Oliver Stone)
1992: White Men Can't Jump
1993: Falling Down
1994: Speed (Keanu Reeves)
1998: The Big Lebowski
1998: American History X
2001: Dogtown and Z-Boys
2003: Thirteen (Holly Hunter)
2004: Grand Theft Auto: San Andreas as Verona Beach
2005: Lords of Dogtown
2006: Tenacious D in The Pick of Destiny
2007: Californication TV series
2011: Wilfred (U.S. TV series)
2013: Grand Theft Auto V as Vespucci Beach
2013: Sugar
2013-2014: Sam & Cat
2009–present: American Ninja Warrior
2014: Alex of Venice
2015: The Amazing Race
2016: Flaked


document_title: Screwdriver

question_text: the flukes of a reed and prince screwdriver are at what angle

text: Screwdriver

text: History[edit]

text: The earliest documented screwdrivers were used in Europe in the late Middle Ages. They were probably invented in the late 15th century, either in Germany or France. The tool's original names in German and French were Schraubendreher (screwturner) and tournevis (turnscrew), respectively. The first documentation of the tool is in the medieval Housebook of Wolfegg Castle, a manuscript written sometime between 1475 and 1490.[2] These earliest screwdrivers had pear-shaped handles and were made for slotted screws (diversification of the many types of screwdrivers did not emerge until the Gilded Age). The screwdriver remained inconspicuous, however, as evidence of its existence throughout the next 300 years is based primarily on the presence of screws.

text: Screws were used in the 15th century to construct screw-cutting lathes, for securing breastplates, backplates, and helmets on medieval jousting armor—and eventually for multiple parts of the emerging firearms, particularly the matchlock. Screws, hence screwdrivers, were not used in full combat armor, most likely to give the wearer freedom of movement.[further explanation needed]

text: The jaws that hold the pyrites inside medieval guns were secured with screws, and the need to constantly replace the pyrites resulted in considerable refinement of the screwdriver. The tool is more documented in France, and took on many shapes and sizes, though all for slotted screws. There were large, heavy-duty screwdrivers for building and repairing large machines, and smaller screwdrivers for refined cabinet work.

text: The screwdriver depended entirely on the screw, and it took several advances to make the screw easy enough to produce to become popular and widespread. The most popular door hinge at the time was the butt-hinge, but it was considered a luxury. The butt-hinge was handmade, and its constant motion required the security of a screw.

text: Screws were very hard to produce before the First Industrial Revolution, requiring manufacture of a conical helix. The brothers Job and William Wyatt found a way to produce a screw on a novel machine that first cut the slotted head, and then cut the helix. Though their business ultimately failed, their contribution to low-cost manufacturing of the screw ultimately led to a vast increase in the screw and the screwdriver's popularity. The increase in popularity gradually led to refinement and eventually diversification of the screwdriver. Refinement of the precision of screws also significantly contributed to the boom in production, mostly by increasing its efficiency and standardizing sizes, important precursors to industrial manufacture.

text: Canadian P.L. Robertson, though he was not the first person to patent the idea of socket-head screws, was the first to successfully commercialize them, starting in 1908. Socket screws rapidly grew in popularity, and are still a favorite of mechanics today for their resistance to wear and tear, compatibility with hex keys, and ability to stop a power tool when set. Though immensely popular, Robertson had trouble marketing his invention to the newly booming auto industry, for he was unwilling to relinquish his patents.

text: Meanwhile, in Portland, Oregon, Henry F. Phillips patented his own invention, an improved version of a deep socket with a cruciform slot, today known as the Phillips Screw. Phillips offered his screw to the American Screw Company, and after a successful trial on the 1936 Cadillac, it quickly swept through the American auto industry. With the Industrial Revival at the end of the Great Depression and the onslaught of World War II, the Phillips screw quickly became, and remains, the most popular screw in the world. A main attraction for the screw was that conventional slotted screwdrivers could also be used on them, which was not possible with the Robertson Screw.

text: Gunsmiths still call a screwdriver a turnscrew, under which name it is an important part of a set of pistols. The name was common in earlier centuries, used by cabinetmakers, shipwrights, and perhaps other trades. The cabinetmaker's screwdriver is one of the longest-established handle forms, somewhat oval or ellipsoid in cross section. This is variously attributed to improving grip or preventing the tool rolling off the bench. The shape has been popular for a couple of hundred years. It is usually associated with a plain head for slotted screws, but has been used with many head forms. Modern plastic screwdrivers use a handle with a roughly hexagonal cross section to achieve these same two goals, a far cry from the pear-shaped handle of the original 15th-century screwdriver.

text: Drive types[edit]

text: Screwdrivers come in a large range of sizes to accommodate various screws—from tiny jeweler's screwdrivers up. A screwdriver that is not the right size and type for the screw may damage the screw in the process of tightening it. Depending on the application, the name of a screwdriver may differ. Within the automotive/heavy electric industries, it is known as a "flat head screwdriver";[citation needed] within the avionics and mining industries, it is known as a "standard screwdriver".[citation needed] Though there are many names, the original device from 1908 was known as a "flat-head screw turner".[citation needed]

text: Some screwdriver tips are magnetic, so that the screw (unless non-magnetic) remains attached to the screwdriver without requiring external force. This is particularly useful in small screws, which are otherwise difficult to handle. Many screwdriver designs have a handle with detachable tip (the part of the screwdriver that engages the screw), called bits as with drill bits. This provides a set of one handle and several bits that can drive a variety of screw sizes and types.

text: Many modern electrical appliances, if they contain screws, use screws with heads other than the typical slotted or Phillips styles. Torx™ is one such pattern that has become widespread. It's a spline tip with a corresponding recess in the screw head. The main cause of this trend is manufacturing efficiency: Torx screwdriver tips do not slip out of the fastener as easily as would a Phillips or slotted driver. (Slotted screws are rarely used in mass-produced devices, since the driver is not inherently centered on the fastener.)

text: Non-typical fasteners are commonplace in consumer devices for their ability to make disassembly more difficult, which is seen as a benefit for manufacturers but is considered a disadvantage by users than if more-common head types were used. In microwave ovens, such screws deny casual access to the high-power kilovolt electrical components, which are very dangerous.

text: However, Torx and other drivers have become widely available to the consumer due to their increasing use in the industry. Some other styles fit a three-pointed star recess, and a five-lobed spline with rounded edges instead of the square edges of the Torx™. This is called a Pentalobe.

text: Specialized patterns of security screws are also used, such as the Line Head (LH) style by OSG System Products, Japan, as used in many Nintendo consoles, though drivers for the more common security heads are, again, readily available. Another type of security head has smooth curved surfaces instead of the slot edges that would permit loosening the screw; it's found in public rest room privacy partitions, and cannot be removed by conventional screwdrivers.

text: Handle[edit]

text: The handle and shaft of screwdrivers have changed considerably over time. The design is influenced by both purpose and manufacturing requirements. The "Perfect Pattern Handle"[further explanation needed] screwdriver was first manufactured by HD Smith & Company, which operated from 1850 to 1900. Many manufacturers adopted this handle design. The "flat bladed" screwdriver was another design composed of drop-forged steel with riveted wood handles.

text: The shape and material of many modern screwdriver handles are designed to fit comfortably in the user's hand, for user comfort and to facilitate maximum control and torque. Designs include indentations for the user's fingers, and surfaces of a soft material such as thermoplastic elastomer to increase comfort and grip. Composite handles of rigid plastic and rubber are also common. Many screwdriver handles are not smooth and often not round, but have flats or other irregularities to improve grip and to prevent the tool from rolling when on a flat surface.

text: Some screwdrivers have a short hexagonal section at the top of the blade, adjacent to the handle, so that a ring spanner or open wrench can be used to increase the applied torque. The offset screwdriver has a handle set at right angles to the small blade, providing access to narrow spaces and giving extra torque.

text: Blade types[edit]

text: The tool used to drive a slotted screw head is called a standard, common blade, flat-blade, slot-head, straight, flat, flat-tip,[3] or "flat-head"[4] screwdriver. This last usage can be confusing, because the term flat-head also describes a screw with a flat top, designed to install in a countersunk hole. Furthermore, the term implies that a screwdriver has a "head"; it does not. Such a flat-headed screw may have a slotted, cross, square recessed, or combination head. Before the development of the newer bit types, the flat-blade was called the "Common-Blade", because it was the most common one.

text: Among slotted screwdrivers, variations at the blade or bit end involve the profile of the blade as viewed face-on (from the side of the tool). The more common type is sometimes called keystone, where the blade profile is slightly flared before tapering off at the end, which provides extra stiffness to the workface and makes it capable of withstanding more torque. To maximize access in space-restricted applications, the cabinet variant screwdriver blade sides are straight and parallel, reaching the end of the blade at a right angle. This design is also frequently used in jeweler's screwdrivers.

text: Many textbooks and vocational schools instruct mechanics to grind down the tip of the blade, which, due to the taper, increases its thickness and consequently allows more precise engagement with the slot in the screw. This approach creates a set of graduated slotted screwdrivers that fit a particular screw for a tighter engagement and reduce screw head deformation. However, many better-quality screwdriver blades are already induction-hardened (surface heat-treated), and tip grinding after manufacture compromises their durability. Thus, it is best to select a tip made to fit precisely to begin with, and avoid weakening the factory heat-treatment.

text: Phillips screwdrivers come in several standard sizes, ranging from tiny "jeweler's" to those used for automobile frame assembly—or #000 to #4 respectively. This size number is usually stamped onto the shank (shaft) or handle for identification. Each bit size fits a range of screw sizes, more or less well. Each Phillips screwdriver size also has a related shank diameter. The driver has a 57° point and tapered, unsharp (rounded) flutes. The #1 and smaller bits come to a blunt point, but the #2 and above have no point, but rather a nearly squared-off tip, making each size incompatible with the other.

text: The design is often criticized for its tendency to cam out at lower torque levels than other "cross head" designs. There has long been a popular belief that this was actually a deliberate feature of the design. Evidence is lacking for this specific narrative and the feature is not mentioned in the original patents.[5] However, a subsequent refinement to the original design described in US Patent #2,474,994[6][7][8] describes this feature.

text: Robertson, also known as a square,[9] or Scrulox[10] screw drive has a square-shaped socket in the screw head and a square protrusion on the tool. Both the tool and the socket have a taper, which makes inserting the tool easier, and also tends to help keep the screw on the tool tip without the user needing to hold it there. (The taper's earliest reason for being was to make the manufacture of the screws practical using cold forming of the heads,[11] but its other advantages helped popularize the drive.) Robertson screws are commonplace in Canada, though they have been used elsewhere [12] and have become much more common in other countries in recent decades. Robertson screwdrivers are easy to use one-handed, because the tapered socket tends to retain the screw, even if it is shaken.[12] They also allow for the use of angled screw drivers and trim head screws. The socket-headed Robertson screws are self-centering, reduce cam out, stop a power tool when set, and can be removed if painted-over or old and rusty.[12] In industry, they speed up production and reduce product damage. One of their first major industrial uses was the Ford Motor Company's Model A & Model T production. Henry Ford found them highly reliable and saved considerable production time, but when he couldn't secure licensing for them in the United States, limited their production use to his Canadian division. Robertson-head screwdrivers are available in a standard range of tip-sizes, from 1.77mm to 4.85mm.

text: Reed and Prince, also called Frearson, is another historic cross-head screw configuration. The cross in the screw head is sharper and less rounded than a Phillips, and the bit has 45° flukes and a sharper, pointed end. Also, the Phillips screw slot is not as deep as the Reed and Prince slot.[13][14][15] In theory, different size R&P screws fit any R&P bit size.[16]

text: Pozidriv and the related Supadriv are widely used in Europe and most of the Far East.[17] While Pozidriv screws have cross heads like Phillips and are sometimes thought effectively the same, the Pozidriv design allows higher torque application than Phillips. It is often claimed that they can apply more torque than any of the other commonly used cross-head screwdriver systems, due to a complex fluting (mating) configuration.

text: Japanese Industrial Standard (JIS) cross-head screwdrivers are still another standard, often inaccurately called Japanese Phillips. Compatible screw heads are usually identifiable by a single depressed dot or an "X" to one side of the cross slot. This is a screw standard throughout the Asia market and Japanese imports. The driver has a 57° point with a flat tip.[18]

text: Variations[edit]

text: Torque screwdrivers[edit]

text: Screwdrivers are available—manual, electric, and pneumatic—with a clutch that slips at a preset torque. This helps the user tighten screws to a specified torque without damage or over-tightening. Cordless drills designed to use as screwdrivers often have such a clutch.

text: Powered screwdrivers[edit]

text: Interchangeable bits allow the use of powered screwdrivers, commonly using an electric or air motor to rotate the bit. Cordless drills with speed and torque control are commonly used as power screwdrivers.

text: Ratcheting screwdrivers[edit]

text: Some manual screwdrivers have a ratchet action whereby the screwdriver blade locks to the handle for clockwise rotation, but uncouples for counterclockwise rotation when set for tightening screws—and vice versa for loosening.

text: Spiral ratchet screw drivers, often colloquially called Yankee screwdrivers (a brand name), provide a special mechanism that transforms linear motion into rotational motion. Originally the "Yankee" name was used on all tools sold by the North Brothers Manufacturing Company but later, after Stanley purchased the company, it became synonymous with only this type of screwdriver. The user pushes the handle toward the workpiece, causing a pawl in a spiral groove to rotate the shank and the removable bit. The ratchet can be set to rotate left or right with each push, or can be locked so that the tool can be used like a conventional screwdriver. One disadvantage of this design is that if the bit slips out of the screw, the resultant sudden extension of the spring may cause the bit to scratch or otherwise damage the workpiece.

text: Once very popular, versions of these spiral ratchet drivers using proprietary bits have been largely discontinued by manufacturers such as Stanley. Some companies now offer a modernized version that uses standard 1/4-inch hex shank power tool bits. Since a wide variety of drill bits are available in this format, the tool can do double duty as a "push drill" or Persian drill.

text: Misuse[edit]

text: Manual straight screwdrivers are commonly abused as improvised substitutes for other tools, such as crow bars or chisels. Screwdrivers are not designed for these purposes, and such use can damage the tip, bend the shaft, or injure the user if the screwdriver slips or breaks.[19]

text: Screwdrivers have also been used as stabbing weapons,[20][21] and are usually tightly restricted in prisons.


document_title: You Shook Me All Night Long

question_text: you shook me all night long video actress

text: You Shook Me All Night Long

text: Critical reception[edit]

text: "You Shook Me All Night Long" placed at number 10 on VH1's list of "The 100 Greatest Songs of the 80s". It was also number 1 on VH1's "Top Ten AC/DC Songs". Guitar World placed "You Shook Me All Night Long" at number 80 on their "100 Greatest Guitar Solos" list.

text: Robert Christgau regarded it as a "drum-hooked fucksong" and the band's "only great work of art".[1]

text: Live versions[edit]

text: The song has also become a staple of AC/DC concerts, and is rarely excluded from the setlist.[2]

text: Four live versions of the song were officially released. The first one appeared on the 1986 maxi-single "You Shook Me All Night Long"; the second one was included on the band's album Live; the third version is on the soundtrack to the Howard Stern movie Private Parts, and also appears on the AC/DC box set Backtracks; and the fourth one is on the band's live album, Live at River Plate.[citation needed]

text: "You Shook Me All Night Long" was also the second song to be played by AC/DC on Saturday Night Live in 2000, following their performance of "Stiff Upper Lip."[3] When AC/DC was inducted to the Rock and Roll Hall of Fame in 2003 by Steven Tyler of Aerosmith, they performed this song with Tyler.[4]

text: Johnson performed the song with Billy Joel at Madison Square Garden in New York, US in March 2014. The Salon publication stated on the following morning in its introduction to the video footage of the performance: "This will either be your favorite video today, or a total musical nightmare!"[5]

text: Composition[edit]

text: The song is in the key G major. The main verse and riff follows a G–C–D chord progression.  The lyrics borrow heavily from the Willie Dixon tune "You Shook Me".

text: Music video[edit]

text: Two versions of the music video exist. The first version, directed by Eric Dionysius and Eric Mistler,[6] is similar to the other Back in Black videos ("Back in Black", "Hells Bells", "What Do You Do For Money Honey", "Rock and Roll Ain't Noise Pollution" and "Let Me Put My Love Into You") and is available on the special Back in Black, The Videos. It is also included on the Backtracks box set.[citation needed]

text: In the second version, directed by David Mallet[7] and released six years after the song's original release, Angus and Malcolm Young follow Johnson around the English town of Huddersfield, with Angus Young wearing his signature schoolboy outfit. The video clip casts the English glamour model Corinne Russell, a former Hill's Angel and Page 3 Girl—along with other leather clad women wearing suits with zips at the groin region—pedaling bicycles like machines in the background.[citation needed]

text: The VH1 series Pop-Up Video revealed that, during the scene with the mechanical bull, the woman playing Johnson's lover accidentally jabbed herself with her spur twice. The roadie who came to her aid married her a year later, and Angus Young gave them a mechanical bull as a wedding present as a joke. The original 1980 video Phil Rudd played drums, while the 1986 video showed Simon Wright, who replaced Rudd in 1983. Rudd returned to AC/DC in 1994.[citation needed]

text: Controversy[edit]

text: Jesse Fink's book Bon: The Last Highway contains claims from two former girlfriends of Bon Scott, Silver Smith and "Holly X" (a pseudonym) that Scott wrote parts of the song before his death on 19 February 1980.[8]

text: Charts and certifications[edit]

text: Weekly charts[edit]

text:
Chart (1980)

Peak  position

Australian Kent Music Report[9]

8

French Singles Chart[10]

5

German Singles Chart[11]

29

Irish Singles Chart[12]

19

UK Singles Chart[13]

38

US Billboard Hot 100[14]

35

text: Year-end charts[edit]

text:
Chart (1980)

Position

Australian Kent Music Report[9]

42

text: Certifications[edit]

text:
Region

Certification
Certified units/Sales

Australia (ARIA)[15]

Platinum

70,000^

Italy (FIMI)[16]

Gold

25,000*

United Kingdom (BPI)[17]

Silver

250,000

United States (RIAA)[18](Mastertone)

Platinum

1,000,000^

*sales figures based on certification alone^shipments figures based on certification alone

text: In popular culture[edit]

text:
The song was featured in "Real Families", a 1980 episode of WKRP in Cincinnati.[19]
The song was released as a vinyl single by the band Slingshot, featuring singer Kathy Kosins, in 1983—the single was distributed only in the United States, Germany, Canada and Italy.[20]
The ending credits of the 1986 horror film Maximum Overdrive played this song throughout.
The song appears in the 2001 movie A Knight's Tale, starring Heath Ledger.[21]
Celine Dion and Anastacia performed a live duet of the song at the 2002 VH1 Divas Las Vegas concert.[22]
Shania Twain covered "You Shook Me All Night Long" in her "Up! Close and Personal" television special in 2003.
American country music duo Big & Rich covered "You Shook Me All Night Long" for their 2007 album, Between Raising Hell and Amazing Grace.[23]
The song is played in season 7, episode 13 of Supernatural, "Slice Girls".[24] It is also used in "The Road So Far" sequence of the season 4 premier "Lazarus Rising."
The song is heard in the television series New Girl.[25]
The song is played in season 1, episode 16 of Mike and Molly.[26]


document_title: Casino Night

question_text: in what episode do pam and jim kiss

question_tokens: in what episode do pam and jim kiss

text: Casino Night

text: Plot[edit]

text: Michael Scott (Steve Carell) organizes a casino charity event in the warehouse, and unwittingly winds up with two dates for the evening, his boss Jan Levinson (Melora Hardin) and his real-estate agent Carol Stills (Nancy Carell). Jim Halpert (John Krasinski) and Pam Beesly (Jenna Fischer) go through audition tapes for her wedding band and discover that colleague Kevin Malone (Brian Baumgartner) has his own band. Jim, upset about Pam's impending marriage to Roy Anderson (David Denman), tells the documentary crew that he met with Jan about transferring to the Stamford, Connecticut branch of Dunder Mifflin because he has "no future here."

text: During Casino Night, Dwight Schrute (Rainn Wilson) wins a game of craps and kisses Angela Martin (Angela Kinsey) on the cheek, disregarding their attempts to keep their intimate relationship a secret. She slaps him and walks away, the two quietly enjoying the experience. Jan and Carol share an awkward conversation when they realize Michael has invited them both. Jim tells Jan that he's made a decision about the transfer. After Roy leaves, Jim tells Pam that he is in love with her. After a stunned pause, she states she cannot be with him. He tells her he wants to be more than friends, but she is sorry he "misinterpreted things." Heartbroken, Jim apologizes for misinterpreting their friendship and discreetly wipes a tear from his cheek as he walks away. Jan leaves Michael and Carol, noticeably upset at the night's events, and it is revealed she packed an overnight bag in her car, implying she had planned to spend the night with Michael. Pam returns to the office and talks to her mother over the phone about Jim's statement. Jim enters the room and approaches her as she hastily hangs up. She begins to say something but Jim kisses her, and after hesitating, she returns the kiss, with the two staring at each other in silence.

text: Production[edit]

text: "Casino Night" was the first episode of the series written by Steve Carell.[2][3] Initially, Carell suggested to executive producer Greg Daniels that an episode should revolve around a casino night. When it came time to plan the finale for the show, Daniels chose the idea and picked Carell to write the script. Parts of the script were fleshed out during the flights to and from New York City when the show was filming the earlier episode "Valentine's Day". Later, Carell had only one weekend to write the bulk script. Daniels was very happy with the rough script and noted "came in with a great draft".[4] Jenna Fischer admitted that filming the episode was a relief because she had "been carrying around the secret cliff-hangers for two months".[3] Toby Flenderson, who is portrayed by writer Paul Lieberstein, stated during the episode "I'm gonna chase that feeling" after winning at a game of poker. The line was originally intended to lead to a subplot wherein Toby develops a gambling addiction, but the storyline was later abandoned.[5]

text: The episode was the fifth episode of the season and the seventh of the entire series directed by Ken Kwapis.[3][6] During the editing of the episode, executive producer Greg Daniels publicly addressed NBC in an interview, stating, "I'd like to get a supersized episode, because it’s a really long script with a lot of good stuff."[7] In response, fans of the show set up an online petition to "supersize" the season finale. The website generated over 2,800 signatures. On April 20, NBC announced it would be extending the season finale by ten minutes.[2] Although other NBC shows Will & Grace and My Name Is Earl that aired on the same night had extended episodes, cast members David Denman and John Krasinski credited in interviews the petition for the extended time. Denman and Krasinski both believed that the petition was partially responsible for the other two shows getting extended times as well.[8]

text: The filming of the episode's ending caused a "huge divide among the writing staff and the director and the cast".[9] Carell, Kwapis, and the actors wanted the moment when Pam and Jim kiss to "follow the characters and the emotion of the moment" by having the action captured in full by the show's cameramen. The writing staff, on the other hand, wanted Pam and Jim's moment to be private and only heard via the mics; Daniels explained, "The writing staff was itching to do something kind of weird [with the scene] and have it be a private moment that the doc crew didn't know was going to happen and so only heard on their mics and came running around the corner to film."[9] Eventually, both versions were filmed, but the former was broadcast. The alternate version has never been released.[9]

text: The episode features Kevin Malone playing the drums in a band, which had been an idea circulated since the first season, when allusions to him being in a Steve Miller tribute band were written; the scenes had to be removed from the series due to issues negotiating with the singer. The crew later decided to have Kevin be in a Police tribute band called Scrantonicity because he "talks so low, and has very little expression, and there is no band that sings higher and with more expression than the Police."[10] While Kevin was always intended to be the band's lead singer, executive producer Greg Daniels approached Baumgartner about possibly playing an instrument, but the actor replied he could not play anything. Daniels and Baumgartner then discussed instruments that would be "funny" to play and brought up harmonicas, saxophones, and drums. They ultimately decided on the latter because they deemed a "drumming lead singer [to] be the funniest choice," regardless of the fact that the actor had "absolutely no drumming experience, and it's a difficult instrument."[10]

text: The Season Two DVD contains a number of deleted scenes from this episode. Notable cut scenes include Michael creating Dunder Mifflin Mad Libs, Dwight and Jim choosing their charities, Dwight considering Jim's telekinetic powers, an extension of Michael's scene with Darryl, Pam finding planning a wedding stressful, Meredith and the casino dealer sharing a past.[11]

text: Cultural references[edit]

text: On the phone with Jan, Michael compares the performance of the Scranton branch of Dunder Mifflin to the biblical story of David and Goliath. He later tells her that she's the "Eva Peron to his Cesar Chavez".[12] He later calls answers his phone while talking to her and says "Jan Levenson, I presume", a reference to "Dr. Livingstone, I Presume".[12] Michael reasons that the money from the casino night should benefit the Boy Scouts of America because "They don't have cookies like the Girl Scouts!"[12] He later states that he will donate all of his charity winnings to Comic Relief, a British charity. Kelly reasons that she would donate her winnings to Kobe Bryant's foundation, only because he bought his wife a large ring.[12]

text: When Michael mentions donating money to "Afghanistanis with AIDS", the conversation gets confused, and the various office workers being talking about Afghanis, Afghans, and the nonsensical "Afghanistanannis".[12] In a talking head, Michael notes that AIDS is not a humorous disease, and is one of the many things that is off-topic in comedy, including the assassination of John F. Kennedy and The Holocaust. However, he notes that the assassination of Abraham Lincoln recently became funny. While looking through the various cover bands, Jim and Pam stumble upon a Kiss tribute and Jim tells Pam that her wedding should have three stages like Lollapalooza. Kevin's band is playing a cover of "Don't Stand So Close to Me" by The Police.[12]

text: Reception[edit]

text: Ratings[edit]

text: "Casino Night" originally aired on NBC in the United States on May 11, 2006.[13] The episode received a 3.9 rating/10 percent share among adults between the ages of 18 and 49.[14] This means that it was seen by 3.9 percent of all 18- to 49-year-olds, and 10 percent of all 18- to 49-year-olds watching television at the time of the broadcast.[14] The episode was viewed by 7.7 million viewers, and retained 93 percent of its lead-in "My Name is Earl" audience.[14] For his work on this episode, Steve Carell was nominated for and won the Writers Guild of America Award for Television: Episodic Comedy.[15]

text: Reviews[edit]

text: "Casino Night" received widespread critical acclaim from television critics. Michael Sciannamea of TV Squad stated that "This episode, the season finale, was, in a word, brilliant. You could not ask for a better way to tie up story lines that occurred over the course of a season while opening up new ones at the same time."[16] Sciannamea went on to praise Carell's writing, as well as the progression of the relationship arcs in the show.[16] Brian Zoromski of IGN said that "'Casino Night,' was full of great character development, awkward situations and laugh-out-loud moments."[17] Zoromski enjoyed the unfolding of the Jim-Pam relationship during the latter half of season two, and the climax of it in the season finale. He also enjoyed and praised the development of two minor characters, Kevin Malone and Creed Bratton, the latter played by the actor of the same name. He ultimately awarded the episode a ten out of ten, denoting a "Masterpiece".[17] Jacob Cliffton of Television Without Pity awarded the episode an "A".[12] Gillian Flynn of Entertainment Weekly noted that, unlike other shows that featured resolved sexual tension, The Office was in no worry of being cancelled. She based this deduction on the fact that the show "isn't based entirely on the endearing flirtation between" Jim and Pam.[18] In a 2011 poll conducted by fansite OfficeTally, fans voted "Casino Night" as their favorite of all Office episodes that had been aired at that time.[19]


document_title: Circular motion

question_text: what does w stand for in circular motion

text: Circular motion

text: Uniform circular motion[edit]

text: In physics, uniform circular motion describes the motion of a body traversing a circular path at constant speed. Since the body describes circular motion, its distance from the axis of rotation remains constant at all times. Though the body's speed is constant, its velocity is not constant: velocity, a vector quantity, depends on both the body's speed and its direction of travel. This changing velocity indicates the presence of an acceleration; this centripetal acceleration is of constant magnitude and directed at all times towards the axis of rotation. This acceleration is, in turn, produced by a centripetal force which is also constant in magnitude and directed towards the axis of rotation.

text: In the case of rotation around a fixed axis of a rigid body that is not negligibly small compared to the radius of the path, each particle of the body describes a uniform circular motion with the same angular velocity, but with velocity and acceleration varying with the position with respect to the axis.

text: Formulas[edit]

text: For motion in a circle of radius r, the circumference of the circle is C = 2π r. If the period for one rotation is T, the angular rate of rotation, also known as angular velocity, ω is:

text: The speed of the object travelling the circle is:

text: The angle θ swept out in a time t is:

text: The angular acceleration, α, of the particle is:

text: In the case of uniform circular motion, α will be zero.

text: The acceleration due to change in the direction is:

text: The centripetal and centrifugal force can also be found out using acceleration:

text: The vector relationships are shown in Figure 1. The axis of rotation is shown as a vector ω perpendicular to the plane of the orbit and with a magnitude ω = dθ / dt. The direction of ω is chosen using the right-hand rule. With this convention for depicting rotation, the velocity is given by a vector cross product as

text: which is a vector perpendicular to both ω and r(t), tangential to the orbit, and of magnitude ω r. Likewise, the acceleration is given by

text: which is a vector perpendicular to both ω and v(t) of magnitude ω |v| = ω2 r and directed exactly opposite to r(t).[1]

text: In the simplest case the speed, mass and radius are constant.

text: Consider a body of one kilogram, moving in a circle of radius one metre, with an angular velocity of one radian per second.

text:
The speed is one metre per second.
The inward acceleration is one metre per square second, v2/r.
It is subject to a centripetal force of one kilogram metre per square second, which is one newton.
The momentum of the body is one kg·m·s−1.
The moment of inertia is one kg·m2.
The angular momentum is one kg·m2·s−1.
The kinetic energy is 1/2 joule.
The circumference of the orbit is 2π (~6.283) metres.
The period of the motion is 2π seconds per turn.
The frequency is (2π)−1 hertz.

text: In polar coordinates[edit]

text:
During circular motion the body moves on a curve that can be described in polar coordinate system as a fixed distance R from the center of the orbit taken as origin, oriented at an angle θ(t) from some reference direction. See Figure 4. The displacement vector

r
→

{\displaystyle {\vec {r}}}

 is the radial vector from the origin to the particle location:

text:
where

u
^

R

(
t
)

{\displaystyle {\hat {u}}_{R}(t)}

 is the unit vector parallel to the radius vector at time t and pointing away from the origin. It is convenient to introduce the unit vector orthogonal to

u
^

R

(
t
)

{\displaystyle {\hat {u}}_{R}(t)}

 as well, namely

u
^

θ

(
t
)

{\displaystyle {\hat {u}}_{\theta }(t)}

. It is customary to orient

u
^

θ

(
t
)

{\displaystyle {\hat {u}}_{\theta }(t)}

 to point in the direction of travel along the orbit.

text: The velocity is the time derivative of the displacement:

text:
Because the radius of the circle is constant, the radial component of the velocity is zero. The unit vector

u
^

R

(
t
)

{\displaystyle {\hat {u}}_{R}(t)}

 has a time-invariant magnitude of unity, so as time varies its tip always lies on a circle of unit radius, with an angle θ the same as the angle of

r
→

(
t
)

{\displaystyle {\vec {r}}(t)}

. If the particle displacement rotates through an angle dθ in time dt, so does

u
^

R

(
t
)

{\displaystyle {\hat {u}}_{R}(t)}

, describing an arc on the unit circle of magnitude dθ. See the unit circle at the left of Figure 4. Hence:

text:
where the direction of the change must be perpendicular to

u
^

R

(
t
)

{\displaystyle {\hat {u}}_{R}(t)}

 (or, in other words, along

u
^

θ

(
t
)

{\displaystyle {\hat {u}}_{\theta }(t)}

) because any change

d

u
^

R

(
t
)

{\displaystyle d{\hat {u}}_{R}(t)}

 in the direction of

u
^

R

(
t
)

{\displaystyle {\hat {u}}_{R}(t)}

 would change the size of

u
^

R

(
t
)

{\displaystyle {\hat {u}}_{R}(t)}

. The sign is positive, because an increase in dθ implies the object and

u
^

R

(
t
)

{\displaystyle {\hat {u}}_{R}(t)}

 have moved in the direction of

u
^

θ

(
t
)

{\displaystyle {\hat {u}}_{\theta }(t)}

. Hence the velocity becomes:

text: The acceleration of the body can also be broken into radial and tangential components. The acceleration is the time derivative of the velocity:

text:
The time derivative of

u
^

θ

(
t
)

{\displaystyle {\hat {u}}_{\theta }(t)}

 is found the same way as for

u
^

R

(
t
)

{\displaystyle {\hat {u}}_{R}(t)}

. Again,

u
^

θ

(
t
)

{\displaystyle {\hat {u}}_{\theta }(t)}

 is a unit vector and its tip traces a unit circle with an angle that is π/2 + θ. Hence, an increase in angle dθ by

r
→

(
t
)

{\displaystyle {\vec {r}}(t)}

 implies

u
^

θ

(
t
)

{\displaystyle {\hat {u}}_{\theta }(t)}

 traces an arc of magnitude dθ, and as

u
^

θ

(
t
)

{\displaystyle {\hat {u}}_{\theta }(t)}

 is orthogonal to

u
^

R

(
t
)

{\displaystyle {\hat {u}}_{R}(t)}

, we have:

text:
where a negative sign is necessary to keep

u
^

θ

(
t
)

{\displaystyle {\hat {u}}_{\theta }(t)}

 orthogonal to

u
^

R

(
t
)

{\displaystyle {\hat {u}}_{R}(t)}

. (Otherwise, the angle between

u
^

θ

(
t
)

{\displaystyle {\hat {u}}_{\theta }(t)}

 and

u
^

R

(
t
)

{\displaystyle {\hat {u}}_{R}(t)}

 would decrease with increase in dθ.) See the unit circle at the left of Figure 4. Consequently, the acceleration is:

text: The centripetal acceleration is the radial component, which is directed radially inward:

text: while the tangential component changes the magnitude of the velocity:

text: Using complex numbers[edit]

text:
Circular motion can be described using complex numbers. Let the x axis be the real axis and the

y

{\displaystyle y}

 axis be the imaginary axis. The position of the body can then be given as

z

{\displaystyle z}

, a complex "vector":

text:
where i is the imaginary unit, and

θ
(
t
)

{\displaystyle \theta (t)}

 is the argument of the complex number as a function of time, t.

text: Since the radius is constant:

text: where a dot indicates differentiation in respect of time.

text: With this notation the velocity becomes:

text: and the acceleration becomes:

text: The first term is opposite in direction to the displacement vector and the second is perpendicular to it, just like the earlier results shown before.

text: Discussion[edit]

text: Velocity[edit]

text: Figure 1 illustrates velocity and acceleration vectors for uniform motion at four different points in the orbit. Because the velocity v is tangent to the circular path, no two velocities point in the same direction. Although the object has a constant speed, its direction is always changing. This change in velocity is caused by an acceleration a, whose magnitude is (like that of the velocity) held constant, but whose direction also is always changing. The acceleration points radially inwards (centripetally) and is perpendicular to the velocity. This acceleration is known as centripetal acceleration.

text: For a path of radius r, when an angle θ is swept out, the distance travelled on the periphery of the orbit is s = rθ. Therefore, the speed of travel around the orbit is

text: where the angular rate of rotation is ω. (By rearrangement, ω = v/r.) Thus, v is a constant, and the velocity vector v also rotates with constant magnitude v, at the same angular rate ω.

text: Relativistic circular motion[edit]

text: In this case the three-acceleration vector is perpendicular to the three-velocity vector,

text: and the square of proper acceleration, expressed as a scalar invariant, the same in all reference frames,

text: becomes the expression for circular motion,

text: or, taking the positive square root and using the three-acceleration, we arrive at the proper acceleration for circular motion:

text: Acceleration[edit]

text: The left-hand circle in Figure 2 is the orbit showing the velocity vectors at two adjacent times. On the right, these two velocities are moved so their tails coincide. Because speed is constant, the velocity vectors on the right sweep out a circle as time advances. For a swept angle dθ = ω dt the change in v is a vector at right angles to v and of magnitude v dθ, which in turn means that the magnitude of the acceleration is given by

text:
Centripetal acceleration for some values of radius and magnitude of velocity

|v|

  r

1 m/s
3.6 km/h
2.2 mph
2 m/s
7.2 km/h
4.5 mph
5 m/s
18 km/h
11 mph
10 m/s
36 km/h
22 mph
20 m/s
72 km/h
45 mph
50 m/s
180 km/h
110 mph
100 m/s
360 km/h
220 mph

Slow walk

Bicycle

City car

Aerobatics

10 cm
3.9 in
Laboratory
centrifuge
10 m/s2
1.0 g
40 m/s2
4.1 g
250 m/s2
25 g
1.0 km/s2
100 g
4.0 km/s2
410 g
25 km/s2
2500 g
100 km/s2
10000 g

20 cm
7.9 in

5.0 m/s²
0.51 g
20 m/s²
2.0 g
130 m/s²
13 g
500 m/s²
51 g
2.0 km/s²
200 g
13 km/s²
1300 g
50 km/s²
5100 g

50 cm
1.6 ft

2.0 m/s²
0.20 g
8.0 m/s²
0.82 g
50 m/s²
5.1 g
200 m/s²
20 g
800 m/s²
82 g
5.0 km/s²
510 g
20 km/s²
2000 g

1 m
3.3 ft
Playground
carousel
1.0 m/s²
0.10 g
4.0 m/s²
0.41 g
25 m/s²
2.5 g
100 m/s²
10 g
400 m/s²
41 g
2.5 km/s²
250 g
10 km/s²
1000 g

2 m
6.6 ft

500 mm/s²
0.051 g
2.0 m/s²
0.20 g
13 m/s²
1.3 g
50 m/s²
5.1 g
200 m/s²
20 g
1.3 km/s²
130 g
5.0 km/s²
510 g

5 m
16 ft

200 mm/s²
0.020 g
800 mm/s²
0.082 g
5.0 m/s²
0.51 g
20 m/s²
2.0 g
80 m/s²
8.2 g
500 m/s²
51 g
2.0 km/s²
200 g

10 m
33 ft
Roller-coaster
vertical loop
100 mm/s²
0.010 g
400 mm/s²
0.041 g
2.5 m/s²
0.25 g
10 m/s²
1.0 g
40 m/s²
4.1 g
250 m/s²
25 g
1.0 km/s²
100 g

20 m
66 ft

50 mm/s²
0.0051 g
200 mm/s²
0.020 g
1.3 m/s²
0.13 g
5.0 m/s²
0.51 g
20 m/s²
2 g
130 m/s²
13 g
500 m/s²
51 g

50 m
160 ft

20 mm/s²
0.0020 g
80 mm/s²
0.0082 g
500 mm/s²
0.051 g
2.0 m/s²
0.20 g
8.0 m/s²
0.82 g
50 m/s²
5.1 g
200 m/s²
20 g

100 m
330 ft
Freeway
on-ramp
10 mm/s²
0.0010 g
40 mm/s²
0.0041 g
250 mm/s²
0.025 g
1.0 m/s²
0.10 g
4.0 m/s²
0.41 g
25 m/s²
2.5 g
100 m/s²
10 g

200 m
660 ft

5.0 mm/s²
0.00051 g
20 mm/s²
0.0020 g
130 m/s²
0.013 g
500 mm/s²
0.051 g
2.0 m/s²
0.20 g
13 m/s²
1.3 g
50 m/s²
5.1 g

500 m
1600 ft

2.0 mm/s²
0.00020 g
8.0 mm/s²
0.00082 g
50 mm/s²
0.0051 g
200 mm/s²
0.020 g
800 mm/s²
0.082 g
5.0 m/s²
0.51 g
20 m/s²
2.0 g

1 km
3300 ft
High-speed
railway
1.0 mm/s²
0.00010 g
4.0 mm/s²
0.00041 g
25 mm/s²
0.0025 g
100 mm/s²
0.010 g
400 mm/s²
0.041 g
2.5 m/s²
0.25 g
10 m/s²
1.0 g

text: Non-uniform[edit]

text: In non-uniform circular motion an object is moving in a circular path with a varying speed. Since the speed is changing, there is tangential acceleration in addition to normal acceleration.

text: In non-uniform circular motion the net acceleration (a) is along direction of Δv which is directed inside circle but does not pass through its center (see figure). The net acceleration may be resolved into two components: tangential acceleration and normal acceleration also known as the centripetal or radial acceleration. Unlike tangential acceleration, centripetal acceleration is present in both uniform and non-uniform circular motion.

text: In non-uniform circular motion, normal force does not always point in the opposite direction of weight. Here is an example with an object traveling in a straight path then loops a loop back into a straight path again.

text: This diagram shows the normal force pointing in other directions rather than opposite to the weight force. The normal force is actually the sum of the radial and tangential forces. The component of weight force is responsible for the tangential force here (We have neglected frictional force). The radial force (centripetal force) is due the change in direction of velocity as discussed earlier.

text: In non-uniform circular motion, normal force and weight may point in the same direction. Both forces can point down, yet the object will remain in a circular path without falling straight down. First let’s see why normal force can point down in the first place. In the first diagram, let's say the object is a person sitting inside a plane, the two forces point down only when it reaches the top of the circle. The reason for this is that the normal force is the sum of the tangential force and centripetal force. The tangential force is zero at the top (as no work is performed when the motion is perpendicular to the direction of force applied. Here weight force is perpendicular to the direction of motion of the object at the top of the circle) and centripetal force points down, thus normal force will point down as well. From a logical standpoint, a person who is travelling in the plane will be upside down at the top of the circle. At that moment, the person’s seat is actually pushing down on the person, which is the normal force.

text: The reason why the object does not fall down when subjected to only downward forces is a simple one. Think about what keeps an object up after it is thrown. Once an object is thrown into the air, there is only the downward force of earth’s gravity that acts on the object. That does not mean that once an object is thrown in the air, it will fall instantly. What keeps that object up in the air is its velocity. The first of Newton's laws of motion states that an object’s inertia keeps it in motion, and since the object in the air has a velocity, it will tend to keep moving in that direction.

text: A varying angular speed for an object moving in a circular path can also be achieved if the rotating body does not have an homogeneous mass distribution. For inhomogeneous objects, it is necessary to approach the problem as in.[2]

text: Applications[edit]

text: Solving applications dealing with non-uniform circular motion involves force analysis. With uniform circular motion, the only force acting upon an object traveling in a circle is the centripetal force. In non-uniform circular motion, there are additional forces acting on the object due to a non-zero tangential acceleration. Although there are additional forces acting upon the object, the sum of all the forces acting on the object will have to equal to the centripetal force.

text: Radial acceleration is used when calculating the total force. Tangential acceleration is not used in calculating total force because it is not responsible for keeping the object in a circular path. The only acceleration responsible for keeping an object moving in a circle is the radial acceleration. Since the sum of all forces is the centripetal force, drawing centripetal force into a free body diagram is not necessary and usually not recommended.

text:
Using

F

n
e
t

=

F

c

{\displaystyle F_{net}=F_{c}\,}

, we can draw free body diagrams to list all the forces acting on an object then set it equal to

F

c

{\displaystyle F_{c}\,}

. Afterwards, we can solve for what ever is unknown (this can be mass, velocity, radius of curvature, coefficient of friction, normal force, etc.). For example, the visual above showing an object at the top of a semicircle would be expressed as

F

c

=
n
+
m
g

{\displaystyle F_{c}=n+mg\,}

.

text: In uniform circular motion, total acceleration of an object in a circular path is equal to the radial acceleration. Due to the presence of tangential acceleration in non uniform circular motion, that does not hold true any more. To find the total acceleration of an object in non uniform circular, find the vector sum of the tangential acceleration and the radial acceleration.

text:
Radial acceleration is still equal to

v

2

/

r

{\displaystyle v^{2}/r}

. Tangential acceleration is simply the derivative of the velocity at any given point:

a

t

=
d
v

/

d
t

{\displaystyle a_{t}=dv/dt\,}

. This root sum of squares of separate radial and tangential accelerations is only correct for circular motion; for general motion within a plane with polar coordinates

(
r
,
θ
)

{\displaystyle (r,\theta )}

, the Coriolis term

a

c

=
2
(
d
r

/

d
t
)
(
d
θ

/

d
t
)

{\displaystyle a_{c}=2(dr/dt)(d\theta /dt)}

 should be added to

a

t

{\displaystyle a_{t}}

, whereas radial acceleration then becomes

a

r

=
−

v

2

/

r
+

d

2

r

/

d

t

2

{\displaystyle a_{r}=-v^{2}/r+d^{2}r/dt^{2}}

.