Gravitational Potential Energy deltaEg=(GMm/r1)-(GMm/r2)

1. May 11, 2010

clearlyjunk

deltaEg=(GMm/r1)-(GMm/r2)

My question is how is it possible to say that in General , Eg=(-GMm/r)

and why does Eg not equal 0 when r -> infinity

Thanks

2. May 11, 2010

rcgldr

Potential energy is the negative of the work done by the force generating the field, which explains why Eg is usually negative. If infinity is used as a reference point, then Eg at infinity is equal to zero, by definition, and all Eg's at finite distance from the source are negative.

3. May 16, 2010

dulrich

Also, infinity is the natural reference point because that is where the interaction drops to zero. No interaction, no ability to do work, no energy.