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Two pulleys system (please check my work)

  1. Oct 14, 2008 #1
    1. The problem statement, all variables and given/known data
    Find the acceleration of the system
    The rope is massless
    The mobile pulley is not massless, it weighs 20 grams.
    Find the accelereation of the system

    2. Relevant equations
    g = 9.8

    3. The attempt at a solution

    for W1:
    Fy = 2T-W1 = ma
    2T-(500+20)*g = (500+20)*a
    2T-520g = 520a (equation 1)

    for W2:
    Fy = W2-T=ma
    T = 300(g-a) (equation 2)

    equation 2 in equation 1 gives
    a = 1,43

    Is it correct?
  2. jcsd
  3. Oct 14, 2008 #2
    i don't think it's correct.. i think there is an error in the tensions, but i don't see
    Last edited: Oct 14, 2008
  4. Oct 16, 2008 #3
    can someone help me?
    I really want to know how to do this =(
  5. Oct 16, 2008 #4
    The equations seem to be OK. The solution is not. Try to solve again the two equations.
    If you show how you solve them I can try to find the mistake, if any.
    Be careful with the units. If you want to get the tension in newtons, the mass should be in kg.
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