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Homework Help: Torque Problem, need to verify answer

  1. Oct 17, 2007 #1
    1. The problem statement, all variables and given/known data
    The circular blade on a radial arm saw is turning at 262 rad/s at the instant the motor is turned off. In 18.0 s the speed of the blade is reduced to 85 rad/s. Assume the blade to be a uniform solid disk of radius 0.130 m and mass 0.400 kg. Find the net torque applied to the blade.

    2. Relevant equations
    Sum torque=moment of inertia X angular deceleration

    3. The attempt at a solution
    a=(Wf-Wi)/t=(85-262)/18=-10 rad/s
    =.5*.4(.13)^2*10 = .0338 Nm
    Last edited: Oct 17, 2007
  2. jcsd
  3. Oct 17, 2007 #2
    I think the moment of inertia for a uniform solid disk is 1/2*m*r^2.
  4. Oct 17, 2007 #3
    my bad, changed.
  5. Oct 17, 2007 #4
    I don't see anything else wrong... but I could be wrong. ^^;
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