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(Hopefully) simple thermodynamics question

  1. Sep 13, 2010 #1
    Suppose you have a piston of ideal gas that's thermally isolated from its surroundings. You compress the gas by pushing down on the piston. Question: Does the temperature of the gas change, and why?

    My answer: YES, it changes. Since [itex]\Delta U = Q + W[/itex], and work was done ON the gas (by compressing it), [itex]\Delta U > 0[/itex]. Since the energy of an ideal gas is only dependent on the temperature of the gas, this implies [itex]\Delta T > 0[/itex].
  2. jcsd
  3. Sep 13, 2010 #2
    Yes, it is increasing because with the piston you increase the momentum of the molecules that are bouncing of it, increasing their speed and with that their kinetic energy, that is like hitting a tennis ball with a racket.
    You see the equation in the right way.
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