perpetual motion


nounMechanics.
  1. 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

1
First recorded in 1585–95

Words Nearby perpetual motion

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2024

How to use perpetual motion in a sentence

  • The poor soldier had one of those eccentric souls which need perpetual motion.

    Juana | Honore de Balzac
  • I suppose I am growing old, for I begin to dislike perpetual motion.

    Paul Patoff | F. Marion Crawford
  • Of course, such a doctrine cannot be true; it would amount to a perpetual motion!

    Time and Tide | Robert S. (Robert Stawell) Ball
  • In fact, it is the old story illustrated, that perpetual motion is impossible.

    Time and Tide | Robert S. (Robert Stawell) Ball
  • Or, perhaps, a still more lively illustration to some readers may be the idea of perpetual motion.

British Dictionary definitions for perpetual motion

perpetual motion

noun
  1. 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

  2. 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

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