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Not your usual Cavendish

  1. Jul 24, 2009 #1
    Would it be possible to determine the value of G by setting two very well know masses side by side on a very well know surface of well known coefficient of friction, in a controlled environment, so that the force applied on the smaller by the larger would be transferred entirely in to heat (minus any molecular rearrangements). And the amount of the heat change in the system could somehow indicate G?
  2. jcsd
  3. Jul 24, 2009 #2
    I don't think the gravitational force between the masses(even if huge) would overcome even static friction in the first place. So no question of heat generation either.
  4. Jul 24, 2009 #3
    If there's a tendency for force to pull regardless if it can, does that create energy being channeled into heat?
  5. Jul 24, 2009 #4
    Force's tendency is to change the momentum. That is what defines it. And if there is no component of displacement in the direction of force, it doesn't do work. Meaning, it doesn't change the energy of the body on which it acts. In this case there is no displacement at all.
  6. Jul 24, 2009 #5
    So If I attach a thick tight rubber band around my body and a telephone pole, I'm not moving towards it so you're saying I don't feel any force? I only feel force when I give in to the pull of the rubber band??
  7. Jul 24, 2009 #6


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    If you are not moving then you are not experiencing a net force. For heat to be dissipated via friction you must be doing work, hence a force applied over distance.
  8. Jul 24, 2009 #7
    I said the force wouldn't be doing any work. Didn't say anything about what you 'feel'. You feel a force when the part of your body subject to the force tries to move while the remaining parts oppose it, whether the entire body gives in or not.
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