Inverse Square law Practice Problems?

I want to practice the Inverse square law. Can you give me a few practice problems. I tried googling it, but there weren't any results.
Please give a few Inverse square law practice problems.
Mostly for light and gravity.
(im in the 8th grade, so don0t give me too hard problems, but not too easy either)
I appreciate your answers, thank you.

springsteen2016-11-06T07:26:02Z

Inverse Square Law Problems

Anonymous2010-02-03T21:54:52Z

calculate the gravitational force field for a star given the potential function phi(r) = -GM(r)/r

assume that the star is spherical symmetric and has a density proportional to r^-3/2