(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

All we know the gravitional potential energy is U=-GMm/r. But when I got confused when I was trying to understand the proof of this equation.

2. Relevant equations

Here's what they did:

W by grativity=GMm(1/r2-1/r1)

Therefore, since △Ugrav=-W by grav, we get

U2-U1=-GMm(1/r2-1/r1)

Let's choose out U=0 reference at infinity.that is , we decide to allow U2→0 as r2→infinity. Then this equation becomes U=-GMm/r

3. The attempt at a solution

Here's my question:

What does it mean by "Let's choose out U=0 reference at infinity.that is , we decide to allow U2→0 as r2→infinity. Then this equation becomes U=-GMm/r"?

Why the U2 would approach to 0 when r2 approached to infinity? And what ti U=0 reference?

Thank you!!!

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# Homework Help: Proof of the equation of gravational potential energy

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