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Homework Help: Moment of Inertia of a Composite Area

  1. Oct 10, 2009 #1
    This is not so much a problem as it is a conceptual question. You're calculating the moment of inertia of a composite shape, lets say a square and a triangle. The square however has a hole inside of it. How does this change the computation of the moment of inertia? This is in a 2-D plane.

    My guess would be that it only affects the area of the square but not any part of the calculation involving x or y.
  2. jcsd
  3. Oct 10, 2009 #2


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    Hi only_huce! :wink:

    Moment of inertia is additive, so you just add for solid shapes, and you subtract for holes.

    In other words: do it for the complete square, then do it for the same material with the shape of the hole, and subtract. :smile:
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