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Homework Help: Rolling object and friction

  1. May 24, 2008 #1
    [SOLVED] Rolling object and friction

    1. The problem statement, all variables and given/known data

    I want to find an expression for the coefficient of friction when this object starts to skid when we pull it with a force F


    3. The attempt at a solution

    Ff = (mju)*Mg

    I found that I can put this into Newton's 2. law for rotation and solve for alpha = 0. But why can't I put it into newton's 2. law for linear motion and solve for alpha = 0 (a = (alpha)*R)?
    Last edited by a moderator: Apr 23, 2017
  2. jcsd
  3. May 24, 2008 #2

    Doc Al

    User Avatar

    Staff: Mentor

    You can certainly apply Newton's 2nd law for translational motion. But "a = (alpha)*R" only applies when it rolls without slipping, which is not the case here.
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