6. Once flow becomes supersonic in a nozzle is it possible to increase the mass flow by decreasing the pressure at the exit? Explain your answer. 7. A) What will happen if a nozzle geometry is such that the pressure predicted at the exit for supersonic isentropic flow is higher than the actual pressure at the exit? B) What will happen if a nozzle geometry is such that the pressure predicted at the exit for supersonic isentropic flow is lower than the actual pressure at the exit? 8. A) What is an under-expanded nozzle exit condition? What flow structure will develop downstream of the nozzle? B) What is an overexpanded nozzle exit condition? What flow structure will develop downstream of the nozzle? 9. A) What is the purpose of a diffuser? B) The efficiency of a diffuser is related to changes in what flow variable? C) What happens if the diffuser throat is too small? (Assume the flow at the inlet is supersonic.) D) What does it mean for a diffuser to start? E) What restriction does starting the diffuser put on the area of the throat? F) Will a diffuser designed for maximum efficiency start? Explain your