question_answer 30)

A fighter plane flying horizontally at an altitude of 1.5 km with a speed  passes directly overhead an antiaircraft gun. At what angle from the vertical should the gun be fired for the shell muzzle speed  to hit the plane ? At what maximum altitude should the pilot fly the plane to avoid being hit ? Take .  

Answer:

Speed of plane . The shell moves along curve . The plane moves along PL. Let them hit after a time t.     Fig. 4.109   For hitting, horizontal distance travelled by the plane = Horizontal distance travelled by the shell. or        Horizontal velocity of plane = Horizontal velocity of shell    or The shell should be fired at an angle of  with the horizontal or  with the vertical. The maximum height of flight of the shell is     Thus the pilot should fly the plane at a minimum altitude of 16 km to avoid being hit by the shell.