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!

Find the moment of inertia of this disk

  1. Apr 12, 2008 #1
    1. The problem statement, all variables and given/known data

    A curcial part of a piece of machinery starts as a flat uniform cylindrical disk of radius R0 and mass M. It then has a circular hole of radius R1 drilled into it. The hole's center is a distance h from the center of the disk. Find the moment of inertia of this disk (with off-center hole) when rotated about its center, C.

    Hint: Consider a solid disk and subtract the hole; use parallel-axis theorem.

    2. Relevant equations
    L=IA


    3. The attempt at a solution

    I spent hours on paper with no end, google "chicken scratch" for proof.
     
  2. jcsd
  3. Apr 12, 2008 #2

    tiny-tim

    User Avatar
    Science Advisor
    Homework Helper

    … one step at a time …

    Hi Quartz! :smile:

    When you're confused, just go one step at a time …

    First step … what is the parallel-axis theorem? :smile:
     
  4. Apr 12, 2008 #3
    Thanks!

    wow great help!! this forum is the bestest!!!!!!!!!!
    so you mean I pretend it's a solid and then subtract the drilled hole?
    then with the theorem and some substitution i can get the answer!?
    wow great, thanks so much.
    too bad i handed this homework in days ago.
    but thank god you could explain it so nicely.
    Borat: NOT.
    my teacher showed it to me, but whatever.

    you people, what's the point of this forum?
     
  5. Apr 12, 2008 #4

    tiny-tim

    User Avatar
    Science Advisor
    Homework Helper

    The point of this forum is not to do your homework for you.

    This is a cooperative forum … we help you to do the work yourself. :smile:

    As rohanprabhu previously pointed out to you:
    And if you handed in the work days ago, why did you ask us only 14 hours ago?
     
  6. Apr 12, 2008 #5
    wans't my original post "04.10.08, 09:32"?
    and I got help from my teacher so there.
     
  7. Apr 13, 2008 #6

    tiny-tim

    User Avatar
    Science Advisor
    Homework Helper

    erm … no … your original post, #1 above, was "yesterday" (that's 04.12
    08) at 08.45, London time (same day, 03.45 New York time).
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Find the moment of inertia of this disk
Loading...