I am not looking so much for answers to problems, but I was sick the day of this lecture and need some clarification. I think I understand what to do, but some support would be great.(adsbygoogle = window.adsbygoogle || []).push({});

1. The problem statement, all variables and given/known data

What is the gravitational force acting on a sphere on particle 'm' located at distance 'r' from center of sphere, assuming it is a uniform sphere of matter that has mass M, radius a, and a concentric cavity of radius a/3.

Solve for r= a/6, r= 2a/3, r= 3a/2

I believe all I need is:

F= G(m1m2/r^2)

I have not attempted to solve, I would like to know it if this is the correct equation to use.

Thanks.

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Gravitation: Which formula exactly?

**Physics Forums | Science Articles, Homework Help, Discussion**