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Homework Help: Statics Problem

  1. May 8, 2006 #1

    Ne0

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    Question:
    Beam AB is subject to a uniform load of 300N/m and is supported at B by column BC. If the static coefficients of friction at B and C are (muB) = .2 and (muc) = .5, determine the force P needed to pull the column BC out from under the beam if P is .25m away from C and .75m away from B. Also the columb BC is 4 meters away from A. Neglect the weight of the members. I have a picture attached so you can get a better idea of the problem.

    I started off by finding the Normal force pushing down on the beam which is (300N/m)x(4m) = 1200N. Form there I am stuck as I don't know how to set up the problem to solve for the force P. I tried to find the sums of the horizontal and vertical forces but that wasn't quite working out as I couldn't figure out how to incorporate the moment of the force P. If I could just get a hint towards the right direction I would appreciate that a lot. Thanks in advance.
     

    Attached Files:

  2. jcsd
  3. May 10, 2006 #2

    Astronuc

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    Staff Emeritus
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    One has to determine the load on the column BC - the distributed load is supported by column BC (right) and the pinned end on the left.

    Then with that load, determine the static forces at B and C, which would oppose P.

    Since P is assymetically located, one must determine the moment imposed by P at either B or C, and which is greater than the opposing force at B or C.
     
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