Question

A projectile tgrown with speed u 20 at an angle 30 from a top of a building 40 m high then the horizontal range of the projectile is

Answer 1

Here, first find the horizontal component of speed which is ucos(theta) = 20 cos30= 20*√3/2 = 10√3.
now apply the formula of Range
R = u^2 sin2theta
= (u cos 30)^2 sin2x30
= (10√3)^2 sin60
= 300 x 1/2 = 150m.