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Homework Help: Rolling Friction?

  1. Jul 12, 2007 #1
    Rolling Friction???

    Can someone explain to me why the frictional force is in the same direction as the acceleration of the center of mass of a rolling object?
  2. jcsd
  3. Jul 12, 2007 #2


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    Staff: Mentor

    It has to be in the same direction in order to create the acceleration, F=ma.

    Are you confused by the combination of the wheel pushing back on the ground patch and the ground patch pushing forward on the wheel patch? If there is a torque applied to the wheel (like an accelerating car), that torque pushes backward on the ground patch, and the ground patch pushes forward on the wheel patch. At least that's the way I think about it.
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