1. Limited time only! Sign up for a free 30min personal 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!

Homework Help: The moment of inertia of a rod that is rotating off the end of the rod.

  1. Nov 8, 2014 #1
    Is there a formula for the moment of inertia? A thin, uniform density rod is rotating about an axis that is off the end of the rod, so it looks a bit like this:

    ------- |
    (------- is the rod and | is the axis of rotation, so the rod is rotating out of the plane of your screen)

    I just have a problem about an ice skater spinning and moving their arms, and I'm not sure how to work out the moment of inertia of the arms. The problem says to model them as two rod-like arms that are attached to the the outside of the torso (modelled as a cylinder)
  2. jcsd
  3. Nov 8, 2014 #2

    Doc Al

    User Avatar

    Staff: Mentor

    Do you know the moment of inertia of a rod about its center of mass? If so, use the parallel axis theorem to find the moment of inertia about the axis that you need.
  4. Nov 8, 2014 #3


    User Avatar
    Gold Member

    If you don't know the parallel axis theorem, you can find the MMOI directly by integration.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted