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Homework Help: Net torque of uniform disk

  1. Oct 22, 2007 #1
    [SOLVED] Net torque of uniform disk

    1. The problem statement, all variables and given/known data
    A uniform disk with a mass of 34.8 kg and a radius of 0.32 m is free to rotate about a frictionless axle. Forces of 90.0 N and 125 N are applied to the disk, as the drawing indicates.

    What is the net torque produced by the two forces?

    2. Relevant equations
    Torque = rFsin(theta)

    3. The attempt at a solution
    I've tried using the equation above...125(0.32)sin90 - 90(0.32)sin90 = 11.2 N*m which is wrong. I know this question is trivial, but I'm pretty frustrated at this point...any help would be great.
    Last edited: Oct 22, 2007
  2. jcsd
  3. Oct 22, 2007 #2


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    Assuming the information given is correct, I agree with you that the magnitude of the torque is 11.2 Nm. My physics text usually considered counterclockwise as positive, with clockwise as the negative direction, so I actually got -11.2Nm. This isn't the problem right? If not I would check that you have the correct information.
  4. Oct 22, 2007 #3
    It's the correct information, and the answer is -11.2. Thanks.
  5. Oct 22, 2007 #4


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  6. Jun 16, 2009 #5
    Re: [SOLVED] Net torque of uniform disk

    What is the magnitude of the angular acceleration of the disk?
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