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Homework Help: Rotational inertia problem

  1. Nov 14, 2005 #1
    A uniform solid disk of radius 4.18 m and
    mass 193 kg is free to rotate on a frictionless
    pivot through a point on its rim.
    The acceleration of gravity is 9.8 m/s2 :

    If the disk is released from rest in the po-
    sition shown by the solid circle, what is the
    speed of its center of mass when the disk
    reaches the position indicated by the dashed
    circle? Answer in units of m/s.

    i tried using the conservation of energy equation to solve this problem.


    i used the diameter of the circle for the h, but i still couldn't find the speed of the center of mass. can anyone help?
  2. jcsd
  3. Nov 14, 2005 #2


    User Avatar
    Homework Helper
    Gold Member

    What is "v"? Won't it be easier if you look at the motion as pure rotation about the pivoted point on the rim?
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