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Homework Help: Tension and Accleration

  1. Nov 20, 2003 #1
    The question states:
    Find the acceleration of the masses shown, given that m1 = 1.0 kg, m2 = 2.0 kg and m3 = 3.0 kg

    m1 and m2 are on a table top connected by a rope, m3 is hanging off of the table connected to m2 by a rope and a pully.

    I have drawn free body diagrams for all of the masses, and have tried

    T1 - W3 = - M3 A
    T1 = (3)(9.8) - (3)(A)

    I am unsure on how to find the tension, it is all that I need to find the acceleration.

    Can someone point me in the right direction on how to find the tension?
  2. jcsd
  3. Nov 20, 2003 #2
    I am assuming that there is no friction on the pulley and that the table is smooth etc. etc.

    In this case, you have a 3.0 Kg mass hangin off a table, connected by a pullet to another 3.0 Kg mass. The tension is the same as the weight of the 3.0 Kg mass hanging off the edge. This is because every force has an equal and opposite reaction force. So in this case T = 3.0*g

    So you are acceleration 6.0 Kg of mass with 3.0*g N of force, for this use F = ma to find the acceleration.

    If I could draw a diagram I could make things a little clearer. Can you take it from here though?
  4. Nov 20, 2003 #3
    That was exactly what I needed.

    Thanks for the help!
  5. Nov 20, 2003 #4
    Happy to help. :smile:
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