Question

IV. Continuity

The mass flow rate and the volume flow rate are always the same in a closed pipe. Why do you think that has to be the case? (Try and think about what might happen if the rates were not the same).

Answer 1

Yes, The mass flow rate and the volume flow rate are always the same in a closed pipe.

Consider an example imagine you have a balloon with a hole. Consider this to be your open system.

if you blow air inside the balloon, some air will escape from the hole. Now, the interesting part: If the rate at which you blow air into the balloon, equals the rate at which the air exits the balloon, the balloon won't get inflated. If the balloon does get inflated, it shows that the rate of entry of air is more than the rate of exit of air and some of the mass of the air that you blew in, is getting accumulated inside the balloon, known as mass accumulation.

same as the The mass flow rate and the volume flow rate are always the same in a closed pipe.

if the rates were not the same it shows that the rate of entry of water is more than the rate of exit of water and some of the mass of the water that you insert in, is getting accumulated inside the pipe and if rate of entry is more than rate of exit the pipe will brust.