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Homework Help: Unwinding Cylinder

  1. Dec 13, 2009 #1
    1. The problem statement, all variables and given/known data
    Find the Linear momentum of an unwinding Cylinder with one end of a string attached to the ceiling. The mass of the cylinder is m and radius r. The cylinder is uniform and there is no slipping.

    2. Relevant equations
    Momentum, P = mv
    moment of inertia , I = 1/2 MR^2

    3. The attempt at a solution
    distance from ceiling to point on cylinder , y = l(length of string unwound)

    so is the momentum simply m*dl(t)/dt?
    Last edited: Dec 13, 2009
  2. jcsd
  3. Dec 13, 2009 #2


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    Yes. Draw a free body diagram, apply Newton's Second Law for rotational and linear motion, find the linear acceleration and use it to find l(t).
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