Question

A rifle with a muzzle velocity of 480 m/s shoots a bullet at a target 45.6 m away. How high above the target must the rifle barrel be pointed to ensure that the bullet will hit the target? Neglect air resistance.

Answer 1

assuming the target is horizontal from the gun.

distance bullet falls:
h=1/2 g t^2 where the time is from
t=45.6/480 seconds

so aim h above the target.