Gravitational potential

  • Thread starter nokia8650
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The image below shows a sketh of gravitation potential (y axis) vs. position:

http://img175.imageshack.us/img175/5717/60413547vb3.th.jpg [Broken]

Can someone please explain why the potential does not equal zero at the neutral point - wouldnt the two potentials cancel each other out?

Thanks
 
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  • #2
D H
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Can someone please explain why the potential does not equal zero at the neutral point - wouldnt the two potentials cancel each other out?
First off, why would you expect it to go to zero? That plot is of

[tex]u(r) = -\left(\frac{GM_e}{|r|} + \frac{GM_m}{|R_m-r|}\right)[/tex]

That function is negative definite: its value is negative for all finite values of r.


Secondly, what do you mean by "neutral point"? This term has multiple meanings.
 
  • #3
tiny-tim
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The image below shows a sketh of gravitation potential (y axis) vs. position:

http://img175.imageshack.us/img175/5717/60413547vb3.th.jpg [Broken]

Can someone please explain why the potential does not equal zero at the neutral point - wouldnt the two potentials cancel each other out?

Thanks

Hi nokia8650! :smile:

Where is the potential being measured from (in other words, where is zero potential)?

Potential is often measured "from infinity" …

in that case, the potential will only be zero at an infinite distance from both the Earth and the Moon. :smile:
 
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