Given that, height of tower,
h=19.6m
Angle of line joining from point of projection to the point of ground with horizontal,
θ = 45°
In
Δ‌AOB,tan‌θ= tan‌45°= ⇒1= ⇒R=h=19.6m where, R be the horizontal distance.
We know that, time taken to reach from point A to B,
t=√ By substituting the values, we get
t=√=2s Now,
Horizontal distance
= Horizontal velocity
× Time
⇒ R = ut
19.6 = u × 2 [By substituting the values of R and t, we get]
∴ Initial velocity,
u=9.8m∕s