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Homework Help: A problem about angular momentum

  1. Jul 1, 2012 #1
    1. The problem statement, all variables and given/known data
    A marble of mass M and radius R is rolled up a plane of angular θ. If the initial velocity of the marble is v, what is the distance l it travels up the plane before it begins to roll back down?


    2. Relevant equations



    3. The attempt at a solution
    I would like to know the details of the motion. The answer is l≈1.3m. But I try the equation -mglsinθ=0-(1/2mv+1/2Iω), the result is about 1.5m. I know it is not the correct way, but I am just confused about the critical condition and how the friction is canceled out.
     
  2. jcsd
  3. Jul 1, 2012 #2

    tiny-tim

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    energy? :wink:
     
  4. Jul 1, 2012 #3
    There is no information about energy in the question offered in An Introduction To Mechanis by Kleppner.
     
  5. Jul 1, 2012 #4

    tiny-tim

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    yes there is

    you know m and v and I and ω, so you know the kinetic energy ! :wink:
     
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