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Homework Help: Atwood machine, solve for angular acceleration

  1. May 20, 2010 #1
    1. The problem statement, all variables and given/known data
    The goal is to solve for angular acceleration with the end variables being m1,m2,m3, R, r, g.
    M2 > M1.
    An atwood machine is a pulley with 2 masses, one on each side.


    2. Relevant equations
    Tnet = I * angular acceleration
    Fnet = ma

    3. The attempt at a solution
    I know you have to solve for both the masses and the pulley itself, but how do you relate them?
     
  2. jcsd
  3. May 20, 2010 #2

    Doc Al

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    Staff: Mentor

    How does the angular acceleration of the pulley relate to the linear acceleration of the masses?
     
  4. May 20, 2010 #3
    It's the same?
     
  5. May 20, 2010 #4

    Doc Al

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    :confused: How can an angular acceleration be the same as a linear acceleration? (But they are simply related though.)
     
  6. May 20, 2010 #5
    I must've misunderstood your question, I simply thought that because the mass is having a linear acceleration downward, therefore causing the pulley to have an angular acceleration, they must be the same :S. I'm bad at this angular stuff :(.
    Angular acceleration the change in angular velocity over time, and angular velocity is the change in angle over time... so..... I still can't relate them :S.
     
  7. May 20, 2010 #6

    Doc Al

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    Staff: Mentor

    Hint: Given the angular acceleration of the pulley, what's the tangential acceleration along its circumference?
     
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