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Homework Help: Static Equilibrium Cable Problem

  1. Mar 24, 2008 #1
    1. The problem statement, all variables and given/known data


    In fig. 13-32, a 50.0 kg uniform square sign, 2.00 m on a side, is hung from a 3.00 m horizantal rod of negligible mass. A cable is attached to the end of the rod and to a point on the wall 4.00 m above the point where the rod is hinged to the wall. (a) What is the tension in the cable? What are the magnitudes and directions of the (b) horizantal and (c) vertical components of the force on the rod from the wall?

    2. Relevant equations

    Net force = zero
    Net torque = zero

    3. The attempt at a solution

    I don't understand how there is a vertical component exerted by the wall onto the rod.
    Last edited: Mar 24, 2008
  2. jcsd
  3. Mar 24, 2008 #2


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    If the weight of the sign was all concentrated at the right corner, there would be no vert comp of the wall on the rod; however, the sign's resultant weight acts thru its c.g., not at the corner. Try summing torques about the top left corner.
  4. Mar 24, 2008 #3
    All right. Thanks so much!
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