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Infinite Rocks

  1. Sep 15, 2010 #1
    If an infinitely large rock is traveling infinitesimally slow along a straight line and an infinitesimally small rock is traveling infinitely fast towards the infinitely large rock along the same axis, is the collision elastic?
  2. jcsd
  3. Sep 15, 2010 #2
    In practice elastic collisions are almost impossible. As far as I know only molecules in the kinetic theory are treated with elastic collisions.

    And terms as "infinitely fast" for matter is not acceptable.
    If you change your words to 'really big', 'really small', 'really slow', and 'really fast', I would say the small rock would just shatter and pulverize.
  4. Sep 16, 2010 #3
    The problem you're setting is just like shooting a bullet in a mountain. What do you think would happen?
  5. Sep 20, 2010 #4
    I think that is why he is specifying the high/low mass and high/low velocity. According to e=mc2 a bullet would have no effect on a mountain. But a bullet travelling at .9999c would have a very noticeable effect on a mountain.

    EDIT: Not that a bullet wouldn't have still a very noticeable effect on a mountain at speeds of lower than .9999c.
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