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Torque question

  1. Feb 5, 2010 #1
    can some one please help me with this for an exam?

    A 33.5 kg block (m1) is on a horizontal surface, connected to a 7.10 kg block (m2) by a massless string. The frictionless pulley has a radius R = 0.081 m and a moment of inertia I=0.110 kgm2.
    A force F = 244.9 N acts on m1 at an angle θ = 29.3°. There is no friction between m1 and the surface. What is the upward acceleration of m2?
    an image is attached

    i wrote force equation for both masses.
    none of the are in equilibrium so each has its acceleration.
    i also wrote one equation for the torque on the pulley. summing
    all torques and equaling to I*alfa.

    problem is i have too many variables. t1 t2 a1 a2 and not enough equations.
    i gotta be missing something.
    even if i unite t1 and t2 into one variable of t1-t2,
    and decide that alfa is the square root of squares of a1 and a2
    i am left with one equation and two variables.

    can anyone explain if i am wrong or what am i missing
    or give a detailed outline of solution?


    Attached Files:

  2. jcsd
  3. Feb 5, 2010 #2


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    Homework Helper

    You can write three equations.
    F*cosθ - T1 = m1*a ........(1)
    T1 - T2 = I*α.......(2)
    T2 - m2*g = m2*a.........(1)
    Now solve for a.
  4. Feb 5, 2010 #3
    thanks. it worked
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