perpetual motion

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perpetual motion

n.
The hypothetical continuous operation of an isolated mechanical device or other closed system without a sustaining energy source.

perpetual motion

n
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

perpet′ual mo′tion


n.
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.
[1585–95]
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.perpetual motion - motion that continues indefinitely without any external source of energyperpetual motion - motion that continues indefinitely without any external source of energy; impossible in practice because of friction
motion - a state of change; "they were in a state of steady motion"
References in periodicals archive ?
China co-production is a perpetual-motion machine of formulaic ideas that has a James Bondian reliance on showing off one exotic international location after another, albeit in the service of an adventure that serves up more slapstick than martinis.
Continuing his shadowboxing, Pacquiao briefly turned into a perpetual-motion machine as he threw combinations.
In his campaign for governor last year, John Kitzhaber proposed what sounded like a perpetual-motion machine: The state would sell bonds to finance energy efficiency projects in public schools, and the savings from reduced fuel and electricity costs would pay off the debt.
Their tendency to buy multiple properties and perpetual-motion lifestyles also increase bed-bug risk.
He is wealthy, having invented a perpetual-motion machine--or at least something closely approximating that impossible ideal.