Why is Pressure Volume Work called P*delta V

[sp3sp2sp]

Why isn't it called deltaP *delta V work? Or deltaP*V work?
Does the expression mean that P is constant while V changes and also what is an example of that?
thanks for any help

 

[russ_watters]

Why isn't it called deltaP *delta V work? Or deltaP*V work?
Does the expression mean that P is constant while V changes...

Yes. There are scenarios where pressure can change along with volume, but you can't have work done with a pressure change and no volume change.

...and also what is an example of that?

A hydraulic or pneumatic piston.

 

[Charles Link]

To the OP @sp3sp2sp You should realize that work is force times distance. In this case pressure is force per unit area, $P=\frac{F}{A}$, and the volume change is the area times $d x$, i.e. $dV=A \, d x$. The area cancels, and we get $dW=P \, dV= F \, d x$.