Question

Q4. State whether the following are true or false with a brief explanation (1-2 sentences).
(i) Given a control volume with one inlet and two exits, the two exits must have identical mass flow rates.
(ii) You are given a control volume with one inlet and one exit such that more ‘mechanical energy’ is coming in than going out (‘mechanical energy’ is the sum of enthalpy, kinetic energy and potential energy per unit mass), but are given no information on the work or heat interactions. The total energy (Ecv) within the control volume must increase with time.
(iii) You are given a control volume where the mass is changing with time but the control volume itself has no heat or work interactions with the surroundings. The total energy within this control volume must also change with time.
(iv) For a one-inlet, one-exit control volume at steady state, the volumetric flow rates must be equal at the inlet and the exit.
(v) An open control volume (i.e., with inlets and exits), by definition, always describes the same region and therefore, the specific volume of matter inside cannot change.

Answer 1