Consider a system consisting of the volume inside an ideal nozzle.

Which fundamental irreversibilities occur within the system?

A. Heat transfer down a temperature gradient
B. Un-restrained expansion
C. Friction
D. Electrical resistance
E. None of the above

Which terms in the Entropy Balance can be neglected?

A. $\frac{\text{d}}{\text{d}t}S$
B. $\sum_i \frac{\dot{Q}_i}{T_i}$
C. $\sum_k \dot{m}_k s_k$
D. $\dot{S}_\text{gen}$