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Homework Help: Angular speed after collision

  1. Jan 28, 2012 #1

    I'm having difficulty with this problem.
    I'm assuming all the kinetic energy of mass m is transferred to rotational kinetic energy after the collision so
    1/2 mv2 = 1/2 I ω2
    where I is now Md2/12 + m(d/2)2 =3/4 md2
    Solving, ω = 2v/√3d
    But the answer should be 2v/3d.


    Attached Files:

  2. jcsd
  3. Jan 28, 2012 #2


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    Homework Helper

    I agree with your answer for moment of inertia, but I think maybe energy is not conserved in the collision. Think of a quantity which is still conserved, even though energy isn't.
  4. Jan 28, 2012 #3
    Got it thanks! :)
    Last edited: Jan 28, 2012
  5. Jan 28, 2012 #4
  6. Jan 28, 2012 #5
    Thanks Spinnor! (:
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