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Homework Help: Rolling constraints problem

  1. Dec 4, 2006 #1
    How can I show that when a ball is rolling without slipping on a horizontal plane, the total horizontal force on the ball must be zero?

    I guess I should consider the ball as a rigid body and combine the equations describing the rotation with the rolling constraints, but how? Can someone give me a starter here?
  2. jcsd
  3. Dec 4, 2006 #2


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    Staff: Mentor

    The statement is not correct. I think you meant to say that it is rolling at a constant velocity without slipping. If it's translational and rotational velocities are constant, then what can you say about F=ma?

    But you can definitely accelerate a ball on a horizontal plane by applying a net force....
  4. Dec 4, 2006 #3
    The problem says nothing about constant velocity, just that the ball is constrained to move on a horizontal plane. Otherwise, a = 0 and F = 0.
  5. Dec 4, 2006 #4
    When the ball is not slipping, you can say something about the normal force.
  6. Dec 4, 2006 #5
    Yeah, equal to mg?
  7. Dec 6, 2006 #6
    edit: nevermind.
    Last edited: Dec 6, 2006
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