A rocket is fired at a speed of 91.0 m/s from ground level, at an angle of 49.0 ° above the horizontal. The rocket is fired toward an 21.4-m high wall, which is located 25.0 m away. The rocket attains its launch speed in a negligibly short period of time, after which its engines shut down and the rocket coasts. By how much does the rocket clear the top of the wall?
well, you know that
y = -g/2v^2 sec^2 θ x^2 + tanθ x
so, plug in x=25 and subtract 21.4