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Moment of inertia of a uniform solid sphere

  1. Jun 10, 2012 #1
    For calculating I of a uniform solid sphere, why can't we use thin spherical shells? When I try to use spherical shells I get (3/5)MR^2. Every single derivation uses thin cylindrical shells and end up with the correct expression((2/5)MR^2) but they never explain why it is correct to use cylindrical shells and not spherical shells.
    Thanks!
     
  2. jcsd
  3. Jun 10, 2012 #2

    haruspex

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    You certainly can get there via spherical shells, but it produces the same answer: 2/5.
    What do you get for the MI of the shell?
     
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