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Homework Help: F= MA problem

  1. Apr 28, 2010 #1
    1. The problem statement, all variables and given/known data

    problem in attachment

    2. Relevant equations

    F= MA

    3. The attempt at a solution

    for m2: F= ma = T + m3g - m2g
    T = -m3g + m2g

    for m1: T = m1a
    a = T/m1
    plug in: a = (-m3g + m2g)/ m1

    All 3 blocks: F = (M + m1 + m2 + m3)a

    final answer: F = (M + m1 + m2 + m3)[(-m3g + m2g)/ m1]

    So yea, I'm thinking this is wrong. Any advice on how to solve this would be appreciated.

    Attached Files:

  2. jcsd
  3. Apr 28, 2010 #2


    User Avatar
    Homework Helper
    Gold Member

    Looks okay to me.

    [Edit: Your answer is generally correct. Realize though that the problem statement gives you the relationship between m2 and m3. So you could simplify your final answer by substituting in this relationship, thus getting rid of the m3 variable.]
    Last edited: Apr 28, 2010
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