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Homework Help: Calculate the magnitude of torque due to friction

  1. Apr 13, 2017 #1
    1. The problem statement, all variables and given/known data
    A rotating flywheel slows down only because of friction in its bearings. At the initial time ti, the angular speed of the flywheel is 2.0 rad/s. The power due to friction at a later time tf is half of the power due to friction at time ti. The angular displacement of the flywheel from ti to tf is 1.5 rad. The rotational inertia of the flywheel is 2.0 kgm2. Assume the torque due to friction is constant. Calculate :
    a) The angular speed of the flywheel at time tf.
    b) The magnitude of the work done by friction from ti to tf.
    c) The magnitude of the torque due to friction.

    2. Relevant equations
    I believe they are the angular velocity equations

    3. The attempt at a solution
    I tried it several times but I couldn't get the correct answer of 2.

    Any help is greatly appreciated midterms are tomorrow :(
  2. jcsd
  3. Apr 13, 2017 #2


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    Staff: Mentor

    Show us the details of one or more of your attempts.
  4. Apr 13, 2017 #3


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    2017 Award

    Which item are you trying to calculate to equal 2? Is it the torque, meaning that you successfully calculated parts a and b? What are the units of 2?
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