What three different mechanisms can cause the entropy of a c

What three different mechanisms can cause the entropy of a control volume to change? Answer: A piston-cylinder device contains nitrogen gas. During a reversible, adiabatic process, the entropy of the nitrogen will increase (never. sometimes/always) The entropy of the working fluid of the ideal Carnot cycle during the isothermal heat rejection process, (increases/decreases remains the same) Steam is accelerated as it flows through an actual (irreversible), adiabatic nozzle. The entropy of the steam at the nozzle exit will be than the entropy at the nozzle inlet, (greater than/equal to/less than) A Boeing 777 cruises at 565mph at 31000ft above sea level assume the speed of sound is 310m/s. A Cessna 172 travels 125mph at 5100ft above sea level, where the speed of sound is 335m/s. Calculate the Mach number for the air flowing across the wings of each aircraft during cruise. Answer:

Solution

1) Reversible aidabatic process means isentropic process, entropy never increase

2) Decreases, in heat rejection process entrpy decreases from S2 to S1

3) Entorpy at exit will Grater than to the entorpy at inlet