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perpetual motion

noun, Mechanics
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
1585-1595
1585-95
Dictionary.com Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2015.
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Examples from the Web for perpetual motion
Contemporary Examples
Historical Examples
  • He devoted a great deal of time to designing mechanical schemes for perpetual motion.

    Perpetual Motion Percy Verance
  • Attempts at perpetual motion may all be regarded as attempts to get round this "third law."

    Pioneers of Science Oliver Lodge
  • Plato believes that the soul is in perpetual motion, but that it is immovable as regards motion from place to place.

  • These facts are all well known to the perpetual motion enthusiast.

    Perpetual Motion Percy Verance
  • It is better than perpetual motion, for it is not only that, but perpetual light and heat.

    Through Space to Mars Roy Rockwood
  • All I want, sir, is to find out the secret of perpetual motion!

    The Storm Aleksandr Nicolaevich Ostrovsky
  • It is not designed as an argument either for or against the possibility of the attainment of perpetual motion.

    Perpetual Motion Percy Verance
  • perpetual motion, bustle and whirl,—I grow dizzy to think of it.

    Vassall Morton Francis Parkman
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
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
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