Question

14. A projectile is aimed from point o at a point a at height h above the ground. When the projectile is fired with speed 20 m/s and angle 600, from o it falls at appoint b on the ground just below a. The height of point a above the ground is

Answer 1

$d=v^{2}sin(2\alpha )/g\\d=20^{2}sin(2*60)/9.8\\d=35.34 m$

In Δ AOB, OB=d=35.34 m;    ∠AOB=60°

So, tan(60°)=AB/d

AB=61.21 m