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Homework Help: Moment of inertia for door hinges

  1. Jan 13, 2012 #1
    How do we find out that the moment of inertia about the hinges of a door with a width w is I=M w2/3.
    I find it like this in a book and also in table for the moments of inertia of homogeneous rigid objects with different geometries (about a long thin rod with rotation axis trough end).
    Thank you.
     
  2. jcsd
  3. Jan 13, 2012 #2

    Doc Al

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    Staff: Mentor

    If you understand how the moment of inertia of the thin rod is found, then just realize that the door can be treated like a bunch of rods. (Imagine the door sliced into thin slits.)
     
  4. Jan 13, 2012 #3
    OK, but i don't understand neither how the moment of inertia of a thin rod is found. Can you explain me please
     
  5. Jan 13, 2012 #4

    Doc Al

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    Staff: Mentor

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