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Homework Help: Direction of the frictional force

  1. Dec 4, 2007 #1
    1. The problem statement, all variables and given/known data


    In the above file, a force at the top of the wheel is acting towards, right, and the friction at the bottom towards left.

    But shouldn't the frictional force at the bottom point towards right?
    2. Relevant equations


    3. The attempt at a solution

    Second question: if a ball is rolling up an inclined plane, does the friction points upwards?
    as it is slowing down the angular velocity so that the ang. velocity could be equal to the linear velocity that is being
    slowed down by the gravity.

    Last edited: Dec 4, 2007
  2. jcsd
  3. Dec 4, 2007 #2

    Shooting Star

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    The dirn of the frictional force will always be as to prevent slippage between the surfaces of the ball and the surface it's rolling on.

    1. You're right.
    2. Again, toward the dirn of the movement of the ball. Gravity is slowing down the ball.
  4. Dec 4, 2007 #3

    I would further confirm this with my professor. Two professors(ours and one who has made those notes) told us that friction is that way.
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