Hi everyone,(adsbygoogle = window.adsbygoogle || []).push({});

Here is the problem: Two masses m and n are initially infinitely far appart from each other. Calculate the amount of work to get them a distance R from each other.

Taking mass m as my reference point, the potential energy of mass n a distance r from m is U(r) = -Gmn/r. Now, if only conservative forces are involved -W = U(r') - U(r) where W is the work need to move a mass a distance r' - r as I understand it. So -W = U(R) - 0 => W = -U(R) = Gmn/R. However, the book where I got this problem from has as the solution -Gmn/R. That means either W = U(r') - U(r) or U(r) = Gmn/r, but these would be contradictions.

Confuzzled here,

e(ho0n3

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

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

# Homework Help: Work and Potential Energy

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