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Homework Help: Torque with sign attached to a rod

  1. May 6, 2013 #1
    1. The problem statement, all variables and given/known data
    a 54.8 kg uniform square sign, 2.00 m on a side, is hung from a 3.00 m 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 fixed to the wall.

    2. Relevant equations

    3. The attempt at a solution
    Ʃτ=Trsin(θ1) -mg(r)(sin(θ2))=0
    cable length=sqrt(4^2 +3^2)=5

    That's wrong...what am I forgetting to do?
  2. jcsd
  3. May 6, 2013 #2


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    What is it you're trying to find ?

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  4. May 7, 2013 #3


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    How far from the wall is the centre of mass of the sign (which weighs 54.8kg, not 54.6)?
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