In physics, the restraint of vibratory motion, such as mechanical oscillations, noise, and alternating electric currents, by dissipating energy. Unless a child keeps pumping a swing, the back-and-forth motion decreases; damping by the air's friction opposes the motion and removes energy from the system. Viscous damping is caused by such energy losses as occur in liquid lubrication between moving parts or in a liquid forced through a small opening by a piston, as in automobile shock absorbers. Hysteresis damping involves energy loss within the moving structure itself. Other types of damping include electrical resistance, radiation, and magnetic damping.

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