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Simple pulley system

  1. Oct 31, 2008 #1
    1. The problem statement, all variables and given/known data

    Hey guys.
    I have the following pulley system (in the pic).
    I wrote down all the equations.
    The thing I don't get is the accelerations equation (a1 = 2*a2). I understand that I can get to this equation somehow by the length of the rope, but how?

    2. Relevant equations

    3. The attempt at a solution

    Attached Files:

  2. jcsd
  3. Oct 31, 2008 #2


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    Science Advisor
    Homework Helper

    Hi asi123! :smile:

    You get it by double-differentiating x1 = 2x2

    and that is simple geometry … when m2 moves a distance x2, m1 moves a distance x1 = 2x2. :smile:
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