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Conservation of Angular Momentum Question

  1. Nov 7, 2003 #1
    An ice skater doing a toe spin with outstretched arms has an angular velocity of 4 rad/s. She then tucks in her arms, decreasing her moment of inertia by 7.5%

    a. What is the resulting angular velocity?
    b. By what factor does the skater's kinetic energy change?

    For a, I use IW = I'W' >> 1(4rad/s) = (1-.075)W', then solve for W'
    I got 4.32 rad/s for W'. I don't know if I'm doing it correctly. Also, I need help on part b.

  2. jcsd
  3. Nov 7, 2003 #2


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    Part a looks ok.

    IIRC the formula for rotational energy is

    The ratio is the old kinetic energy divided by the new kinetic energy.
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