1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

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
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?