Thermodynamics question

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1. Oct 5, 2014

Arun Raja

1. The problem statement, all variables and given/known data

2. Relevant equations
Conceptual qn
3. The attempt at a solution

work is done in gas but how can internal energy change?
there is no heat flow since it is an adiabatic process

2. Oct 10, 2014

Greg Bernhardt

Thanks for the post! Sorry you aren't generating responses at the moment. Do you have any further information, come to any new conclusions or is it possible to reword the post?

3. Oct 10, 2014

Staff: Mentor

From the first law, for an adiabatic process, $\Delta U=-W$, where W is the work done by the gas on the surroundings. In this situation, W is negative (the surroundings do work on the gas), so that $\Delta U$ is positive. The temperature of the gas actually rises, even though no heat was transferred to the gas. This is the same thing that happens when you compress air with a bicycle pump.

Chet