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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 Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2018.
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Examples from the Web for perpetual motion
Contemporary Examples
Historical Examples
  • That's the way they did when I was working on the perpetual motion machine.

    Watch Yourself Go By Al. G. Field
  • He called it a breakthrough in the field of perpetual motion.

    With No Strings Attached Gordon Randall Garrett (AKA David Gordon)
  • Attempts at perpetual motion may all be regarded as attempts to get round this "third law."

    Pioneers of Science Oliver Lodge
  • It is the closest approach to perpetual motion I have come across.

    The Iron Ration

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

    Perpetual Motion Percy Verance
  • It is sufficient for the purpose of a perpetual motion that they can do this.

    Perpetual Motion Percy Verance
  • The subject of perpetual motion claimed some of his attention.

    Perpetual Motion Percy Verance
  • All I want, sir, is to find out the secret of perpetual motion!

    The Storm Aleksandr Nicolaevich Ostrovsky
British Dictionary definitions for perpetual motion

perpetual motion

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
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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