Physically Powered Motor
Some motors are powered by potential or kinetic energy, for example some funiculars, gravity plane and ropeway conveyors have used the energy from moving water or rocks, and some clocks have a weight that falls under gravity. Other forms of potential energy include compressed gases (such as pneumatic motors), springs (clockwork motors) and elastic bands.
Historic military siege engines included large catapults, trebuchets, and (to some extent) battering rams were powered by potential energy.
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Famous quotes containing the words physically and/or motor:
“All men are partially buried in the grave of custom, and of some we see only the crown of the head above ground. Better are the physically dead, for they more lively rot. Even virtue is no longer such if it be stagnant. A man’s life should be constantly as fresh as this river. It should be the same channel, but a new water every instant.”
—Henry David Thoreau (1817–1862)
“This biplane is the shape of human flight.
Its name might better be First Motor Kite.”
—Robert Frost (1874–1963)