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

  1. May 11, 2010 #1
    Im not talking about eg=mgh.. im 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 :)
     
  2. jcsd
  3. May 11, 2010 #2

    rcgldr

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    Homework Helper

    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.
     
  4. May 16, 2010 #3
    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.
     
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