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Rotational Inertia question

  1. Jan 31, 2016 #1
    This isn't actually a homework problem, but I am still posting it here. I am confused by rotational inertia. How does mass distribution affect rotational inertia? Because I know it should, but I don't know how it would.
  2. jcsd
  3. Jan 31, 2016 #2
  4. Feb 1, 2016 #3


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    What is rotational inertia? What does it measure regarding an object?
  5. Feb 1, 2016 #4
    What do you mean by "rotational inertia"? Do you mean "moment of inertia"?
  6. Feb 1, 2016 #5
    I'm pretty sure the OP is talking about the moment of inertia.
  7. Feb 2, 2016 #6


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    CrazyNinja they are the same thing. Moment of inertia = rotational inertia.
  8. Feb 2, 2016 #7
    Please elaborate a little more on your problem @ZurasE
  9. Feb 2, 2016 #8
    See, when a mass has to rotate about an axis a centripetal force is required; this force is given by F= mr(omega)^2
    So for a given angular speed ( omega) greater force is required to rotate a body which is at a greater distance.
    Now regarding rotational inertia ( which is the same as moment of inertia), as the mass distribution moves away from the axis(of rotation) the moment of inertia increases ( in other words its resistance to rotation increases)
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