(20 pts) air enters a convergent-divergent nozzle at 20 × 105 n/m2 and 40 ◦c. the receiver pressure is 2 × 105 n/m2 and the nozzle throat area is 10 cm2 . (a) what should the exit area be for the design conditions above(i. e.,to operate at third critical? ) (b) with the nozzle area fixed at the value determined in part (a) and the inlet pressure held at 20 × 105 n/m2 , what receiver pressure would cause a shock to stand at the exit? (c) what receiver pressure would place the shock at the throa