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Homework Help: Rotational Inertia Problem-PLEASE HELP

  1. Jan 12, 2008 #1
    Rotational Inertia Problem--PLEASE HELP!!!!

    1. The problem statement, all variables and given/known data

    Figure 12-39 shows a rigid structure consisting of a circular hoop, of radius R and mass m, and a square made of four thin bars, each of length R and mass m. The rigid structure rotates at a constant speed about a vertical axis with a period of rotation of 1.0 s. Assuming R = 0.50 m and m = 3.0 kg, calculate the structure's rotational inertia about the axis of rotation

    The figure is attached

    2. Relevant equations

    I of point mass = mr^2
    I of hoop = mr^2 or .5mr^2
    I of rod = 1/3 mr^2

    3. The attempt at a solution

    I tried to add the I of the hoop and two of the rods together (because the other two rods are parallel to the rotating axis) but nothing that I've tried really worked...
     

    Attached Files:

  2. jcsd
  3. Feb 13, 2008 #2
    http://panda.unm.edu/Courses/Price/Phys160/p27-2.pdf" [Broken]
     
    Last edited by a moderator: May 3, 2017
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