Gravitation — Science STD 9 — Question

Ball attains the maximum height after 3s. After attaining this height, it will start falling downwards.
In this case,
Initial velocity, u = 0
Position of the ball after 4s of the throw is given by the distance travelled by it
during its downward journey in 4s - 3s = 1s.
Equation of motion, s = ut + 1/2 gt² will give,
s = 0 × t + 1/2 × 9.8 × 1² = 4.9m
Total height = 44.1m
This means that the ball is 39.2m (44.1m - 4.9m) above the ground after 4 seconds.