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

[clearlyjunk]

Im not talking about eg=mgh.. I am talking about

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

please reply quickly :)

 

[rcgldr]

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

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.

 

[dulrich]

If infinity is used as a reference point...

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.