# Non-quasistatic process. Constant pressure.Work cero.

Tags:
1. Oct 18, 2014

### Phyba

If in a non-quasistatic process the pressure is constant, is the work necessarily equal to cero?
I have from the notes taken in class that it must be 0, but I don't really see why, so I'm not sure whether maybe I didn't hear it well.
I haven't really started to work with non-quasistatic processes yet; we were just given the definition of quasistatic process the other day.

Thanks!

2. Oct 18, 2014

### ehild

No. The work is zero if the volume is constant. The work done by the gas at constant pressure is $P \Delta V$, but P is defined only if the process is quasistatic.
The work done on the gas by the surrounding atmosphere at pressure P is $- P \Delta V$.

ehild