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Homework Help: Atwoods MAchine with two pulleys and three masses

  1. Oct 30, 2008 #1
    1. The problem statement, all variables and given/known data
    A system contains two pulleys, over the first pulley there is mass 3, m_3, on one end of the rope. the other end of that rope is connected to the second pully. Hung on the second pulley are mass 2, m_2, and mass 1, m_1. Find the acceleration constraint in terms of a_1 and the tension in the string of the second pulley.

    2. Relevant equations

    3. The attempt at a solution
    the change in the string over pulley 1 causes a_3=.5*a_2 and a_2=a_1 (not sure?)
    so a_1=2a_3?
  2. jcsd
  3. Oct 30, 2008 #2
    I would suggest first drawing free body diagrams for all the masses involved, then using those to find the net force on the masses (and relate the net force to accelerations of the objects using the equation you give). You'll get a number of equations that you'll just have to substitute into each other to find the relationship (constraint) you desire. Seeing those steps in more detail would be productive.
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