2- A converging-diverging nozzle is attached to a reservoir containing air at 300kPa and 300K. The areas of the throat and the exit are, respectively, 5cm2 and 10cm2. a) What is the range of back pressure for the nozzle to be choked? b) What is the maximum mass flow rate the nozzle can deliver? c) What is the range of back pressure for a normal shock wave to exist in the nozzle? d). What should the back pressure be for a normal shock wave to stand where the cross-sectional area is 7.5cm2 ? e). What is the back pressure for perfect expansion