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: Conservation of angular momentum book problem

  1. Dec 8, 2015 #1
    1. The problem statement, all variables and given/known data

    2. The attempt at a solution

    I set the initial angular momentum of the disk = to the sum of : rod's angular momentum, angular momentum of disk, rod's center of gravity and disk's center of gravity. With the reference point being at B.

    Why is the velocity of the rod's center of gravity not included in the solution?

    Thanks for any and all help.
  2. jcsd
  3. Dec 8, 2015 #2
    It has already been taken into account because the moment of inertia used for the rod was 1/3ML2. If the MOI used was 1/12ML2 then you can add the angular momentum contribution from the velocity of the rod's center of mass. This is essentially the application of the Parallel-Axis Theorem.

    Hope this helps!
  4. Dec 8, 2015 #3
    Thanks Jeremy, that completely clears things up. Cheers!
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted