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...)
The following are images from various transport-related articles on Wikipedia.
Image 1Customized motorcycle to maximize load capacity. Mobility is important for motorcycles, which are primarily used for transporting light cargo in urban areas. (from Transport)
Image 2A 16th-century mine-cart, an early example of un-powered rail transport, used man power to operate. (from Rail transport)
Image 12The engineering of this roundabout in Bristol, United Kingdom, attempts to make traffic flow free-moving.
Image 13According 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 14The Beijing Subway is one of the world's largest and busiest rapid transit networks. (from Transport)
Image 15Swiss & German co-production: world's first functional diesel–electric railcar 1914 (from Rail transport)
Image 16A prototype of a Ganz AC electric locomotive in Valtellina, Italy, 1901 (from Rail transport)
Image 27German 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)
Image 28An ambulance from World War I (from Transport)
Image 33The Polish transport company Bedmet uses a special vehicle to transport two large silos. (from Road transport)
Image 34A 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 38Bardon 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 64The 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)
The Moscow Metro in Moscow, Russia, is the world's most heavily used metro system. It is well known for the ornate design of many of the stations (such as Kievskaya Station, pictured), containing stunningly beautiful examples of socialist realist art. In total, the Moscow Metro has 277.9 km of route length, 12 lines and 171 stations. Although passenger traffic is considerably lower on weekends, on a normal weekday the Metro carries 10.05 million passengers, bringing the average daily passenger traffic per year to 8,745 million passengers per day. Moscow Metro is a state-owned enterprise.
... 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?
