Q4 This is a multiple-choice question that consists of seven questions with the total Marks of 15. Q4.1 An explosive induced a moving shock with velocity of 650m/s propagate in stationary air with temperature of 25C. The gas behind this shock is flow with velocity of: A. 388m/s B. 467m/s C. 189m/s D. 260m/s (Marks 3) Q4.2 - When the normal shock wave take place in a duct the following flow parameters will change accordingly: A. Stagnation temperature increase B. Stagnation pressure decrease C. Static temperature increase D. Critical area decrease. E. Entropy increase (Marks 2) Q4.3-A projectile moves down a gun barrel with a velocity of 500 m/s. The shock wave will precede the projectile with the velocity of : A. 355 B. 263 C. 758 D. 1054 Air, V-0 (Marks 2) Projectile Q4.4- When compressible fluid at stagnation condition is expanded adiabatically through a convergent nozzle the terminal velocity at the exit can be expressed by the following equation: A. Ve= (y-1)/y - B. Ve = Pe (1+Me)/ C. Ve = me (To-Te) D. Ve= 2y R (TO-Te) (y-1) (Marks 2) Where: Ve= exit plan velocity. Po is the stagnation pressure. Pe Static exit plan pressure, Me Mach number, po, pe stagnation and static density. me mass flow rate. R is gas constant and y is the specific heat ratio, To, Te is the stagnation and static temperature.