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Dec16-12, 06:54 PM
P: 184
Where does the energy go if I raise and lower a block?

Quote Quote by HallsofIvy View Post
Basically, it is inefficiencies in your muscle that account for your not getting the energy "back". It goes into increased heat in your body, a little increased heat in the air, because of air resistance, and, if you let the block hit the ground "hard", increased heat in the ground and block.

Generally, the answer to "where does the energy go" is "into heat".
Okay, let's say my arm was perfectly efficient. Or let's say that the block is a magnet that we suspend on top of a perfectly efficient electro magnet that strengthens and weakens in it's field, causing the block to move up and down. Basically what I'm saying is, if there are no inefficiencies, where does the energy go?