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Homework Help: Angular momentum/kinetic energy

  1. Jun 30, 2009 #1
    1. The problem statement, all variables and given/known data
    An ice skater holds two weights in his outstretched hands and rotates about his vertical axis. Then he brings the weights closer to his hands.In accordance with the law of conservation of angular momentum,the angular velocity of the ice skater increases.But so does the rotational kinetic energy.Where does this extra energy come from?

    2. Relevant equations

    3. The attempt at a solution
  2. jcsd
  3. Jun 30, 2009 #2


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    Homework Helper

    The muscles in his hands do work on the weights to bring them closer. this will increase the rotational kinetic energy.
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