perpetual motion machines

A perpetual motion is a motion of enduring physical objects that are very large compared with atoms, that continues indefinitely. This is impossible because of friction and other modes of degradation or disruption of form. A perpetual motion machine is a hypothetical machine that can do work indefinitely without an energy source. This kind of machine is impossible, as it would violate the first or second law of thermodynamics.

Perpetual motion is motion that continues indefinitely without any external source of energy.