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Homework Help: Calculating Net Torque of Uniform Disk

  1. Mar 6, 2010 #1
    The circular blade on a radial arm saw is turning at 265 rad/s at the instant the motor is turned off. In 12.0 s the speed of the blade is reduced to 85 rad/s. Assume the blade to be a uniform solid disk of radius 0.140 m and mass 0.400 kg. Find the net torque applied to the blade.

    Relevant Equations:
    Torque net = 0
    Torque= F(r)
    F=ma
    angular accel. = w2r

    Attempt:
    [tex]\sum[/tex]Torque=(.4)(265)2(.14)(.14) +(.4)(85)2(.14)(.14)
    I known I need to sum the forces but I am unsure of what direction to use.
     
  2. jcsd
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