Given: Speed of the cannon, u = 240 m/s The cannon fires a projectile which hits the target located 5.1 km away at the same level. Thus, from projectile motion, we have the range as: R = 5.1 km =
u2sin(2θ)
g
⇒ sin (2θ) =
5100m×9.8m∕s2
(240m∕s)2
= 0.88 ⇒ 2θ = 60° or θ = 30° The time period of a projectile is given as T =