Someone know this proof?

[MusashiStyle]

standard but i forgot it,

I know there is no gravitational force on a point mass anywhere within a uniform density spere radius r, does anyone have the proof on this (with calculus please). also, for density linear function of r if u know that too.

Thanks,

m

[bigpooch]

A useful link is:

http://en.wikipedia.org/wiki/Shell_theorem

[MusashiStyle]

[ QUOTE ]
A useful link is:

http://en.wikipedia.org/wiki/Shell_theorem

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perfect thx!