wheel is a circular component that is intended to rotate on an axial bearing. The wheel is one of the main 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 are found in transport applications. A wheel greatly 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.
Contents
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• 1 Etymology
• 2 History
o 2.1 Images
• 3 Mechanics and function
• 4 Construction
o 4.1 Rim
o 4.2 Hub
o 4.3 Spokes
▪ 4.3.1 Wire
o 4.4 Tire
• 5 Alternatives
• 6 Symbolism
• 7 Gallery
• 8 See also
• 9 References
• 10 External links
Etymology[edit]
The English word wheel comes from the Old English word hweol, hweogol, from Proto-Germanic *hwehwlan, *hwegwlan, from Proto-Indo-European *kwekwlo-,[1] an extended form of the root *kwel- "to revolve, move around". Cognates within Indo-European include Greek κύκλος kýklos, "wheel", Sanskrit chakra, Old Church Slavonic kolo, all meaning "circle" or "wheel",[2]
History[edit]
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A depiction of an onager-drawn cart on the Sumerian "battle standard of Ur" (c. 2500 BC)
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A figurine featuring the New World's independently invented wheel
Evidence of wheeled vehicles appears from the mid-4th millennium BC, near-simultaneously in Mesopotamia, Indus Valley(Moenjodaro), the Northern Caucasus (Maykop culture) and Central Europe, so that the question of which culture originally invented...