A brake is a device for slowing or stopping the motion of a machine. The kinetic energy lost by the moving part is usually translated to heat by friction. Alternatively, in regenerative braking[?], the energy is recovered and stored in a flywheel, capacitor or other device for later use.
Brakes of some description are fitted to most wheeled vehicles, including automobiles of all kinds, trains, motorcycles, and bicycles. Some aeroplanes are fitted with wheel brakes on their landing wheels. Some also feature air brakes designed to slow them down in flight (notable examples include some WWII-era fighter aircraft which used "dive brakes" to allow the planes to maintain a safe speed in a steep descent).
See also Bicycle brake systems
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