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Apparent creation of energy

  1. Apr 21, 2005 #1
    My Question has to do with the apparent creation of energy;

    Say if one were to some how find a large rock in deep space (where no other gravitational fields existed) and bring it into the proximity of a large mass, say a star, It would be safe to say that it would accelerate towards this star, gaining KE and losing GPE.

    The question lies here; where did this energy come from? As no work was done to raise the object above the star where did the GPE come from?

    Does GPE exist when an object is far from the reaches for the Grav field?
    On this line of reasoning can we say that all objects in the universe have GPE with respect to every other body?
    Last edited: Apr 21, 2005
  2. jcsd
  3. Apr 21, 2005 #2


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    Total energy does not change. The rock had potential energy proportional to it's original distance from the star. Moving the rock closer to the star decreases its potential energy and so increases its kinetic energy.
  4. Apr 23, 2005 #3
    Here's more on how to work with conservation of total energy

  5. Apr 23, 2005 #4
    The Potencial Energy does not exist physically, as the name says it is the potencial of energy that a mass will aquire. Anyway, a mass never reaches its maximum kinetic energy since it hits the surface of the attracting mass first and cannot make it to the center.
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