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Moment of inertia equation?

  1. Oct 6, 2014 #1
    Moment of inertia is
    I = MR2
    object has more mass means more inertia and less mass means less inertia.
    That means moment of inertia is directly proportional to mass.
    But how the moment of inertia is directly proportional to the square of the distance.?
     
  2. jcsd
  3. Oct 6, 2014 #2

    Doc Al

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    Staff: Mentor

    For a point mass, not in general.

    OK.

    Only if the distance to the axis--the R--is fixed.

    It's a measure of the torque required to produce a given rotational acceleration. Loosely: The further the mass is from the axis, the harder it is to get it to rotate.
     
  4. Oct 6, 2014 #3
    but why it is square of the distance rather than only distance.
     
  5. Oct 6, 2014 #4

    Doc Al

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    Staff: Mentor

  6. Oct 6, 2014 #5
    Thanks. It helpful for me.
     
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