Paul Fuller <pgf### [at] optusnetcomau> wrote:
> As the part is spun up, the larger part is spun in the opposite 
> direction to a degree determined by their relative masses.  The net 
> angular momentum of the system stays constant assuming that this is a 
> closed system.

  You assume that the rotation can be done without any friction. This is,
in fact, impossible in practice.

  Friction produces heat. Heat is energy. This energy must come from
somewhere.

  Even if the Earth-Moon system was a completely isolated closed system
in space, Earth's rotation would still slow down. Why? (Granted, the
situation is not identical, but the basic cause for the slowdown is.)

-- 
                                                          - Warp

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