# Perpetual motion in spaces of different gravity?

Imagine two locations with different amounts of gravity. I carry up a weight in low gravity, move it on this height over to the other place, and let it fall down there with higher gravity.

Wouldn't falling down release more energy than lifting up hast cost? If so, is it theoretically possible to generate such a transition between different levels of gravity near to each other?

• No, the amount of energy needed to lift up the object is exactly the same as the energy released when it falls back down again (ignoring air friction etc). This is because gravity is a conservative force. Jan 21 '14 at 7:45
• @JohnRennie So lifting the ball up in a less gravity location would take the same amount of work I could get out of the falling ball in the high gravity location? Jan 21 '14 at 11:01
• Yes, but moving the ball from the low to the high gravity locations would take work, and that would make up the difference. Jan 21 '14 at 11:14
• Oops, sorry I misread your comment. Lifting the ball in the low gravity location takes less work than you get back from dropping it in the high gravity location. However moving it from the low to high gravity location and back takes work. The amount of work lifting the ball plus the work moving it adds up to the same as the work you get back by dropping the ball. Jan 21 '14 at 15:33
• @JohnRennie couldn't I use two ramps to let the ball roll from one side to another? Their slope could be minimal to not waste heights. Jan 21 '14 at 20:38