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Homework Help: Work done by torque

  1. Oct 2, 2012 #1
    1. The problem statement, all variables and given/known data
    In the figure shown a square plate of mass M and side of length L
    is fixed at the center . The force F makes the square plate rotate.
    The force is always perpendicular to the side.
    Find the work done by the force.

    2. Relevant equations
    Work = torque x θ

    3. The attempt at a solution
    I considered the moment arm to be half of the diagonal of length L/√2
    Then the force acting perpendicular to it will be F/√2
    Torque =FL /2 but then how do i find the angle covered?
    The book's answer is (3F2t2)/M

    Attached Files:

    Last edited: Oct 2, 2012
  2. jcsd
  3. Oct 2, 2012 #2
    There is t in the solution but is not stated in the question.
  4. Oct 2, 2012 #3
    The torque is constant, so the the angular acceleration is constant. So you can obtain it as a function of time.
  5. Oct 5, 2012 #4
    Can please be more elaborate ?
    I reaaly appreciated your help,Thanks.:smile:
  6. Oct 5, 2012 #5
    I am not sure what else I could say without solving the entire problem. What is the equation relating angular acceleration and torque?
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