1,3,5,15 5.7 PROBLEMS by Section 5.7 Problems 185 5.1 A projectile moves down a gun barrel with a velocity of 500 m/s. (See Figure P5.1.) Calcu- late the velocity of the normal shock that would precede the projectile Assume the pres- sure in the undisturbed air (y = 1.4, R = 287 J/kg K) to be 101 kPa and the temperature to be 25°C. How fast would the projectile have to be moving in order for the shock veloc- ity to be two times the projectile velocity? Air, V = 0 Figure P5.1 P₁ = lolkpa Projectile T= 25c