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Homework Help: Moment of inertia about x=y=z

  1. Jul 9, 2006 #1
    I'm attempting to find the moment of inertia of a solid about the line x=y=z, but cannot figure out a formula to for distance between a point and the line x=y=z. I tried to simply by first looking at it in two dimensions, but I still haven't come up with anything. Any suggestions are appreciated.

  2. jcsd
  3. Jul 9, 2006 #2


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    So, the distance between a point and a line is measured perpendicular to the line. So the first thing you should do is find the plane perpendicular to the line. Then project the vector from the origin to the point onto this plane. The projection is just the vector between the point and the line.
  4. Jul 11, 2006 #3
    Thanks StatusX, I was able to figure it out.
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