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Homework Help: 2011 F = ma Contest Question # 25

  1. Jan 23, 2012 #1
    1. The problem statement, all variables and given/known data

    A hollow cylinder with a very thin wall (like a toilet paper tube) and a block are placed at rest at the top of a plane with inclination  above the horizontal. The cylinder rolls down the plane without slipping and the block slides down the plane; it is found that both objects reach the bottom of the plane simultaneously. What is the coefficient of kinetic friction between the block and the plane?

    2. Relevant equations

    K = (1/2)MV^2 + (1/2)IW^2 for I = MR^2 and W = V/R

    3. The attempt at a solution

    Answer is: (1/2)tan(theta)
    I have tried many different approaches: F = ma as well as assuming the same mass and/or velocity at the end of the ramp, but have had no success. Thanks for your time and consideration!
  2. jcsd
  3. Jan 23, 2012 #2

    Doc Al

    User Avatar

    Staff: Mentor

    Start by finding the acceleration of the rolling cylinder.
  4. Jan 23, 2012 #3
    Hey, thanks for the response! That really helped and I was able to figure this one out finally.
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