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Rate of spinning

  1. Mar 24, 2008 #1
    A bug that has a mass mb = 4 g walks from the center to the edge of a disk that is freely turning at 21 rpm. The disk has a mass of md = 12 g. If the radius of the disk is R = 30 cm, what is the new rate of spinning in rpm?

    Can I have some help please?
  2. jcsd
  3. Mar 24, 2008 #2
    Try using conservation of anugular momentum. Also remember that moments of inertia add, so the moment of the inertia for your system is the moment of disk + moment of bug.
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