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Homework Help: Rotational Inertia worked it many times.

  1. Oct 31, 2011 #1
    1. The problem statement, all variables and given/known data

    In the figure below, the pendulum consists of a uniform disk with radius r = 10 cm and mass 480 g attached to a uniform rod with length L = 500 mm and mass 260 g.

    2. Relevant equations

    3. The attempt at a solution

    I'm going to cut to the chase.

    I'm basically going with:

    I = 1/2MR^2 + M(R+l)^2 + ml^2 / 3

    Where M and R are mass and radius of disk and m and l are mass and length of rod.

    My final answer has come to .14653 every time, and it is wrong.
  2. jcsd
  3. Oct 31, 2011 #2
    They snuck cm/mm in there, never mind.

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