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Homework Help: Rotational Equilibrium and Dynamics -

  1. Jan 19, 2006 #1
    Rotational Equilibrium and Dynamics - :)

    I'm totally stumped!
    A skater spins with an angular speed of 12.0 rad/s with his arms outstretched. He lowers his arms, decreasing his moment of inertia from 41 kg·m² to 36 kg·m²

    Calculate his initial and final rotational kinetic energy.
    Is the formula KE=1/2·I·ω² ?
    ω=angular speed.. so ω=12.0 rad/s
    so then how would i get I (inertia) ?
    and how would i find out initial and final ?
    i just need some help :grumpy:
    Last edited: Jan 19, 2006
  2. jcsd
  3. Jan 20, 2006 #2
    its given. read the question

    Use conservation of Angular momentum.
  4. Jan 20, 2006 #3
    hmm, i think i get it

    so.. i use (plug in) 41 kg·m² to get my initial and 36 kg·m² to my my final?
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