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Gravitational Potential

  1. Jun 23, 2013 #1
    Gravitational potential is always a negative value according to the theory.
    As per to the equation V = - [itex]\frac{GM}{r}[/itex]; when the r (distance) increases the potential decreases. But considering the potential at infinity as zero and since this a negative value, on what basis do we consider the potential is decreasing, not increasing (When the distance is increasing)?
     
  2. jcsd
  3. Jun 23, 2013 #2

    jtbell

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    No. As r increases, 1/r decreases, but -1/r increases.
     
  4. Jun 24, 2013 #3

    sophiecentaur

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    i.e. it's less negative.
     
  5. Jun 24, 2013 #4

    jtbell

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    ...or slopes upward (has a positive slope) on a graph of V versus r.
     
  6. Jun 24, 2013 #5

    sophiecentaur

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    'Everywhere' is the equivalent of 'underground', effectively and up is up, however deep or high you are.
     
  7. Jun 25, 2013 #6
    So as the negative value decreases, potential is increasing accordingly?

    Let's say that the potential on earth surface is Va = -[itex]\frac{GM}{R}[/itex] and if we move to a higher place where the distance is twice, the potential is Vb = -[itex]\frac{GM}{2R}[/itex]. But at Vb, the negative value is smaller than Va, Vb has a higher potential. Right? :smile:
     
  8. Jun 25, 2013 #7

    sophiecentaur

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    It's exactly the same as when you deal with xy co ordinates. Moving tp the right is increasing the x co ordinate, whether you start on the right or to the left of the origin. Just let the Maths work for you.
    And you really mean 'magnitude'.
     
  9. Jun 30, 2013 #8
    Yep. I got answers. Thank you all!!! :D
     
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