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At 2012/04/28 5:13|
"But wait a minute, if you push on a wall, and it doesn't move, you're still doing work." |
Unfortunately that statement is incorrect. Check your physics textbook, work can only occur if there is motion involved. In this instance you are merely exerting a force; your muscles will tire and have no work to show for it.
At 2012/04/30 11:46|
As I explained in the article, the motion happens inside your muscles, where individual muscle fibers are moving like crazy. Each fiber only moves little, but across a large number of fibers, it adds up to a lot of work.
This is a very common mistake in many physics problems, to "hide" part of the mechanism from our analysis, and it's possible to draw many improper conclusions when we make this mistake.
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