Question

An enemy plane is flying horizontally at an altitude of 2.0km with a speed of 340m/s.An
army man with anti-craft gun on the ground
sight the enemy with a muzzle speed at 60m/s
.when the enemy plane is directly
overhead.find
a)at what angle from the verticals should the
gun be fired so as to hit the plane.
b)at what minimum altitude should the enemy
fly to avoid being hit(take g=10m/s^2)

Answer 1

Vi = initial up speed = ? cos A
u = constant horizontal component = ? sin A
s = horizontal airplane speed=340
T = flight time for both

horizontal problem:
340 T = u T = ? T sin A

so sin A = 340/(? ) which is kind of obvious :)

now the vertical problem:
h = 0 + Vi t -.49 t^2