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Prelab rotational motion question

  1. Oct 21, 2014 #1
    There is an experimental set up that looks like the attitude file.
    1) for mass hanging down the pulley write newton's second law
    2)since the sensor measures α find substitute a with a variable containing α
    3) for the drum (horizontal pulley) find another equation for torque other than τ = Iα
    4) combine eqn 1-3 to find an equation for τ via, T, a, r and α

    The attempt at a solution
    1) ma=mg-T
    2) a = αr
    3) τ = Tr
    4) τ = m(g-αr) r

    Attached Files:

  2. jcsd
  3. Oct 21, 2014 #2

    Simon Bridge

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    Science Advisor
    Homework Helper

    That would be the torque exerted at the rim of the pulley by the hanging mass.
    Looks OK to me - if you have doubts, try to reason through what the equations mean.
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