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: Moment of inertia for Concave Polygon

  1. Apr 9, 2008 #1
    [SOLVED] Moment of inertia for Concave Polygon

    While working on a simulation I ran into this problem. I'm trying to calculate the moment of inertia for a concave polygon. The polygon is made of N vertices (Also the edges are straight lines). I've done a bit of researching however I've only found resources for convex polygons.

    I'm thinking of triangulating the polygon and then going from there, but I don't know how to actually use it.

    I will be grateful for any help on a general way of calculating the moment of inertia for a concave polygon

  2. jcsd
  3. Apr 9, 2008 #2


    User Avatar
    Science Advisor
    Homework Helper

    If you triangulate the polygon, can't you just sum the moments of the triangles? In the case of simple polygons you can also use the trick of trying to decompose it into two convex polygons, where one is the place where material is, and the other is the place where it isn't and add them with opposite signs.
  4. Apr 13, 2008 #3
    Ah yes, I was over thinking it. Thanks for your help
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook