A mortar shell needs to be dropped into a bunker at an angle of 80 degree from level ground. The bunker is 100 yards away. How much velocity must the shell leave the cannon to accomplish this task?

Answer 1

If same height at both ends, symmetric parabolic path.

Goes 100 yards? I guess I use obsolete units, 300 feet and g = 32 ft/s^2

Vi = V sin 80 = .984 V
u = V cos 80 = .174 V

300 feet = u t
300 = .174 V t

how long does it take?
h = Vi t - 16 t^2
h = 0 at start and finish
16 t^2 -Vi t = 0
t (16 t-Vi) = 0
t at target = Vi/16

Vi = .984 V
so t = .0615 V
and
300 = .174 V (.0615 V)
V^2 = 28034
V = 167 feet/second