Question

The ans is,, v= 22.5 km.p.h

but,, how???

Answer 1

Along vertical
Initial velocity = 0

Time taken to fall is
t = sqrt(2h/g)
= sqrt[2 × 2 m / (10 m/s^2)]
= 0.64 seconds

Along horizontal, velocity is constant
Velocity = Displacement / Time
= 4 m / 0.64 s
= 6.25 m/s

Convert above velocity in m/s to kmph
v = 6.25 × 18/5 kmph
= 22.5 kmph