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Homework Help: Which pulley system requires the least force to lift the same weight?

  1. Mar 16, 2012 #1
    1. The problem statement, all variables and given/known data


    2. Relevant equations

    Force applied on the weight=F*(MA).

    3. The attempt at a solution
    i chosse the E system ...it has the greater mechanical advantage (MA)=3.
    MA(of A)=1, MA(of B)=2,MA(C)=2,MA(D)=2,MA(E)=3..
    I hope my suggestions are correct !!! :)
  2. jcsd
  3. Mar 16, 2012 #2
    I agree with you. The 'trick' in these question is to ignore the pulley connected to the ceiling, this pulley simply changes the direction of the rope.
    Count the number of strings holding up the weight, in E it is 3..... Therefore this needs the smallest tension in the string (1/3 the weight)
  4. Mar 16, 2012 #3


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    Gold Member

    What do you think F = m a hass to do with this problem?
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