A wheel is a rotating component (typically circular in shape) that is intended to turn on an axlebearing. The wheel is one of the key components of the wheel and axle which is one of the six simple machines. Wheels, in conjunction with axles, allow heavy objects to be moved easily facilitating movement or transportation while supporting a load, or performing labor in machines. Wheels are also used for other purposes, such as a ship's wheel, steering wheel, potter's wheel, and flywheel.
Common examples can be found in transport applications. A wheel reduces friction by facilitating motion by rolling together with the use of axles. In order for wheels to rotate, a moment needs to be applied to the wheel about its axis, either by way of gravity or by the application of another external force or torque. (Full article...)
Image 3Arizona - North America - Southwest - Interstate Highway System (4893585908) (from Road transport)
Image 4The Great North Road near High gate on the approach to London before turnpiking. The highway was deeply rutted and spread onto adjoining land. (from Road transport)
Image 6Passengers waiting to board a tube train on the London Underground in the early 1900s (sketch by unknown artist)
Image 7Bardon Hill box in England (seen here in 2009) is a Midland Railway box dating from 1899, although the original mechanical lever frame has been replaced by electrical switches. (from Rail transport)
Image 9A cast iron fishbelly edge rail manufactured by Outram at the Butterley Company for the Cromford and High Peak Railway in 1831; these are smooth edge rails for wheels with flanges. (from Rail transport)
Image 14European rail subsidies in euros per passenger-km for 2008 (from Rail transport)
Image 15According to Eurostat and the European Railway Agency, the fatality risk for passengers and occupants on European railways is 28 times lower when compared with car usage (based on data by EU-27 member nations, 2008–2010). (from Rail transport)
Image 16Customized motorcycle to maximize load capacity. Mobility is important for motorcycles, which are primarily used for transporting light cargo in urban areas. (from Transport)
Image 17Lilienthal in mid-flight, Berlin c. 1895 (from Aviation)
Image 19German soldiers in a railway car on the way to the front in August 1914. The message on the car reads Von München über Metz nach Paris ("From Munich via Metz to Paris"). (from Rail transport)
... that a section of Mississippi Highway 489 was designated as the Jason Boyd Memorial Highway to commemorate the MDOT superintendent who was killed while removing debris from the road?
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