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Homework Help: Rotational Motion- Pulleys with Friction

  1. Oct 8, 2007 #1
    1. The problem statement, all variables and given/known data
    Two Masses are suspended from a pulley. The pulley itself has a mas of .20kg a radius of .15m a constant torque of .35 MN due to the friction between the rotating pulley and its axle. What is the magnitude of the acceleration of the suspended masses if m1= .4kg and m2= .8 kg (neglect the mass of the string)
    Pulley
    | |
    | |
    M2 M1




    2. Relevant equations
    T1= M1G - M1A
    T2= M2G + M2A
    Torque= FL = Moment of Inertia x Alpha,
    I= 1/2 mr^2

    3. The attempt at a solution
    I have tried solving this by solving for A when T2-T1= I alpha, but i really dont know how to apply the fact that the tension is different of both cords due to the friction on the pulley im stuck...
     

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  3. Oct 8, 2007 #2
    I have tried everything... but still i cant get to the answer.. i get to the formula a=(m2-m1)g/(1/2M+m1+m2) but after that i dont know how to apply the torque... :( need help
     
    Last edited: Oct 8, 2007
  4. Oct 8, 2007 #3
    bump....
     
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