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一质点在铅垂平面内作圆周运动,当质点恰好转过一周时,其重力的功为零,对吗?为什么?

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正确答案:

对的。因为重力的功等于质点的质量与其始末位置的高度差的乘积,当高度差为零时,重力的功为零。

答案解析:

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