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Homework Help: Mass needed for static equilibrium compound pulley system

  1. Mar 5, 2015 #1
    1. The problem statement, all variables and given/known data
    For what m1 will the illustrated pulley system be in static equilibrium if m2 = 60 kg?

    2. Relevant equations

    3. The attempt at a solution
    im supposed to use the change in lengths but dont know how to do it

    Attached Files:

  2. jcsd
  3. Mar 5, 2015 #2


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    Staff: Mentor

    If it is static (no motion) then the lengths will not be changing. Look to free body diagrams and tensions instead.
  4. Mar 5, 2015 #3
    thanks a lot
  5. Mar 5, 2015 #4


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    Science Advisor
    Homework Helper
    2017 Award

    Hello hus, welcome to PF :smile:

    The change in length thingy is a good hint, though. But perhaps a little differently: If one of the two moves a little, does the other move just as much, half as much, or twice as much ? From that you can deduce the proper tension force to keep balance. And balance means no change of lengths allright.
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