A fighter plane flying horizontally at an altitude of 1.5 km with speed `720 km *h^(-1)` passes directly over an anti-aircraft gun. At what angle with the vertical should the gun be fired for the shell with muzzle speed `600 m*s^(-1)` to hit the plane? At what minimum altitude should the pilot fly the plane to avoid being hit ? (Take `g=10 m*s^(-2)`).

Answer

at an angle of `sin^(-1)(1/3)=19.5^@` with the vertical ; 16km