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Upward Force required to break static friction

  1. Jul 26, 2011 #1
    1. The problem statement, all variables and given/known data

    What is the upward force required to make pipe start to move?

    There is a fixed point and a 36 inch shaft. The force would be applied 36 inches away to the point. The load is 1700lbs. The end point only needs to come up enough so that the static friction of the pipe is broke so that they start to roll and will be close together.

    2. Relevant equations
    downward force= 1700lbs
    static friction=.78 (not sure if this is right)

    3. The attempt at a solution


    Last edited: Jul 26, 2011
  2. jcsd
  3. Jul 26, 2011 #2


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    Welcome to PF! Unfortunately, your question is poorly phrased--a picture would surely be most helpful. Assuming you will provide that, do show the work you have done, so help can be provided, per PF rules.
  4. Jul 26, 2011 #3
    here is the only pic i have. from the little circles is the 36 inches. I just need enough upward lift and force so that the pipes start to move. Hope this better explains my problem.


    Attached Files:

  5. Jul 28, 2011 #4


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    Use one of the equilibrium equations (which one?) to solve for the force at which the shaft will just start to rotate. Assume the pipes are equally spaced. The pipes will start to roll when rolling friction is exceeded, at an angle that is not being asked for, but which could be found if you knew the rolling friction coefficient. When the force is given in pounds, do not multiply by 9.8.
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