perpetual motion

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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.

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Origin of perpetual motion

First recorded in 1585–95

Words nearby perpetual motion

perpetual calendar, perpetual check, perpetual debenture, perpetual inventory, perpetually, perpetual motion, perpetual-motion machine, perpetuate, perpetuation, perpetuity, perphenazine

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2022

How to use perpetual motion in a sentence

For instance, a counterfactual property imposed by the laws of physics is that it is impossible to build a perpetual motion machine.
Our Little Life Is Rounded with Possibility - Issue 102: Hidden Truths|Chiara Marletto|June 9, 2021|Nautilus
In the current approach to physics, some laws already have this counterfactual structure — the conservation of energy, for example, is the statement that it is impossible to have a perpetual motion machine.
How to Rewrite the Laws of Physics in the Language of Impossibility|Amanda Gefter|April 29, 2021|Quanta Magazine
For an artist in perpetual motion, that doesn’t sound like a stretch at all.
There’s no stopping Twyla Tharp, even as she approaches 80|Peter Marks|March 18, 2021|Washington Post
I wonder what that lady is doing now, and if she knows what she set in motion with Archer?
‘Archer’ Creator Adam Reed Spills Season 6 Secrets, From Surreal Plotlines to Life Post-ISIS|Marlow Stern|January 8, 2015|DAILY BEAST

But millions of rules result in perpetual error, and, as a terminal side effect, make leadership and accomplishment illegal.
Red Tape Is Strangling Good Samaritans|Philip K. Howard|December 27, 2014|DAILY BEAST
The train was already in motion as she tried to step inside, and her body was crushed beneath it.
Riding Thailand’s WWII Death Railway|Liza Foreman|December 21, 2014|DAILY BEAST
Stop-motion animation artist PES has unveiled a new short this week.
‘Sexual’ Barbershop Quartet, a Panda Family Reunion, and More Viral Videos|The Daily Beast Video|December 14, 2014|DAILY BEAST
Big discounts and cheap credit keep them coming back for more; and keep millions in perpetual debt.
Christmas Is the New Subprime|Doug McIntyre|December 9, 2014|DAILY BEAST
In this situation we waited the motion of the enemy, without perceiving any advancement they made towards us.
The Life and Most Surprising Adventures of Robinson Crusoe, of York, Mariner (1801)|Daniel Defoe
These sections also have vibrations of their own which are of shorter length and more rapid motion.
Expressive Voice Culture|Jessie Eldridge Southwick
Felipe watched over her as a lover might; her great mournful eyes followed his every motion.
Ramona|Helen Hunt Jackson
At six o'clock I felt once more the welcome motion of a Railroad car, and at eight was in Venice.
Glances at Europe|Horace Greeley
The inheritance of the children of sinners shall perish, and with their posterity shall be a perpetual reproach.
The Bible, Douay-Rheims Version|Various

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

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