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!

Calculating the Moment of Inertia

  1. Apr 3, 2010 #1
    1. The problem statement, all variables and given/known data

    The four masses shown in the attachment are connectec by massless, rigid rods.

    a) find the coordinates of the center of mass.
    b) find the moment of inertia about a diagonal axis that passes through mass B and D.

    2. Relevant equations

    I=MR^2...I think.

    3. The attempt at a solution

    I've solved part a which ended up being 0.0517m, 0.0517m.

    Part b is where I am stumped.

    I've tried [tex]I=M_{A}R^{2}_{A}+M_{B}R^{2}_{B}+M_{C}R^{2}_{C}+M_{D}R^{2}_{D}[/tex] using both the radius of the rods as well as the radius of the center of mass, but neither works.

    I know I am doing this wrong and it's probably a conceptual thing, but I can't see it. :confused:
     

    Attached Files:

  2. jcsd
  3. Apr 3, 2010 #2

    Filip Larsen

    User Avatar
    Gold Member

    The R's in your equation should be the distance from the rotation axis to the mass in question.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Calculating the Moment of Inertia
Loading...