1. The problem statement, all variables and given/known data Consider a tube of uniform cross section, let one end (a) of the tube is at height h1 and other end (b) is at height h2, where h2>h. Now an incompressible fluid passing through the tube the workdone to pass the liquid at end (a) P1V1 and workdone to pass the liquid at end (b) is -P2V2. So the net workdone is P1V1-P2V2= pressure energy, am I right? The negative sign indicate that at point (b) resists the motion of fluid at (b) How? What is the reason it resists the motion of fluid at (b)?