Because the force of gravity performs work (as in hydroelectric power) does the force require some kind of energy source in order to maintain its existence. If there is not an energy source, doesn't this mean it is a perpetual motion force?
2006-12-14 08:33:25 · 2 answers · asked by Anonymous in Science & Mathematics ➔ Physics
Gravity requires only mass. However, if you consider that m = E/c², you could reason that because the mass is equivalent to energy, gravity requires energy.
2006-12-14 12:05:44 · answer #1 · answered by Steve 7 · 1⤊ 0⤋
A gravitational field conserves energy. In the example of the hydroelectric facility, it required heat energy from the sun to elevate the water molecules at sea-level to the elevated level of the dam. Some of that energy is recovered when the water falls through the turbines in the dam.
If you move against the gravity field, you gain potential energy. If you move with the gravity field, you gain kinetic energy. It’s an even swap, although there may be subtle losses along the way. Of course it requires energy to move against a gravitational field, but, at least theoretically, you are trading it for potential energy and can get it back later by falling with the field.
The only thing required for gravity is the presence of mass. It may be possible to produce a gravitational field without mass, but I don’t know anyone who knows how to do that yet.
2006-12-14 16:46:45 · answer #2 · answered by hevans1944 5 · 2⤊ 0⤋