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Homework Help: Multiple Pulleys and Multiple Weights Problem

  1. Sep 24, 2013 #1
    1. The problem statement, all variables and given/known data

    Solve for T (The force required to keep the pulleys at equilibrium)

    See attached image for pulley setup.

    2. Relevant equations


    3. The attempt at a solution

    Currently I have drawn out all the forces that act on each pulley, and I know there is a way to set up the tensions to solve for T, but since no numerical values are given its a little more complicated.
    After applying force diagrams to the hanging weights I got T1=W1g and T3=W2g (with T1 being the tension between Pulley 1 and weight 1, and T3 being the tension between Pulley 2 and weight Which would mean T2=(W2g-W1g)/2, and T2 is the same tension as T, meaning T2 is equivalent to the downward force needed to keep the system at equilibrium. Is this the correct solution?
  2. jcsd
  3. Sep 24, 2013 #2
    for some reason the attachment wouldnt load in original post so here it is again.

    Attached Files:

  4. Sep 25, 2013 #3


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    Science Advisor
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    Gold Member

    That's right, except that if the Ws are weights, not masses, then you don't multiply by g.
  5. Sep 25, 2013 #4
    Okay makes sense, thanks for confirming.
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