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Homework Help: Acceleration and Friction of a Rolling Cylinder

  1. Mar 5, 2012 #1

    hm8

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    1. The problem statement, all variables and given/known data
    A lawn roller in the form of a thin-walled, hollow cylinder with mass M is pulled horizontally with a constant horizontal force F applied by a handle attached to the axle.

    a)If it rolls without slipping, find the acceleration.

    b)If it rolls without slipping, find the friction force.


    2. Relevant equations
    [itex]I_{Hollow Cylinder} = MR^{2}[/itex]

    [itex]\sum \tau = f_{friction}R = I\alpha = MR^{2}\alpha[/itex]

    [itex]\sum F = F - f_{friction} = F = Ma[/itex]



    3. The attempt at a solution
    I'm really not sure...it seems like I have too many unknowns (R, a, alpha, friction)
     
  2. jcsd
  3. Mar 5, 2012 #2

    hm8

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    Ok, so I just remembered that because its not slipping, I can change [itex]\alpha[/itex] to [itex]\frac{a}{r}[/itex]

    so I get [itex]f_{friction}R = MR^{2}*\frac{a}{R}[/itex]

    which cancels down to [itex]f_{friction} = Ma[/itex]

    But when I plug that back into the other equation I just get F - ma = ma.....

    where did I go wrong?
     
  4. Mar 6, 2012 #3

    hm8

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    Any help, guys?
     
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