perpetual motion
noun Mechanics.
the motion of a theoretical mechanism that, without any losses due to friction or other forms of dissipation of energy, would continue to operate indefinitely at the same rate without any external energy being applied to it.
Origin of perpetual motion
First recorded in 1585–95
Words nearby perpetual motion
Example sentences from the Web for perpetual motion
British Dictionary definitions for perpetual motion
perpetual motion
noun
Also called: perpetual motion of the first kind
motion of a hypothetical mechanism that continues indefinitely without any external source of energy. It is impossible in practice because of friction
Also called: perpetual motion of the second kind
motion of a hypothetical mechanism that derives its energy from a source at a lower temperature. It is impossible in practice because of the second law of thermodynamics