Non-quasistatic process. Constant pressure.Work cero.

[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!

 

[ehild]

If in a non-quasistatic process the pressure is constant, is the work necessarily equal to zero?

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