Question

A stone fallas from a cliff and travels 24.5 m in the last second before it reaches the ground at the foot of the cliff.find the height of the cliff?

Answer 1

Height of the tower = H
Total time taken to reach the ground = T

H = 0.5gT^2 ——(1)

H - 24.5 = 0.5g * (T - 1)^2
0.5gT^2 - 24.5 = 0.5g * (T^2 + 1 - 2T)
0.5gT^2 - 24.5 = 0.5gT^2 + 0.5g - gT
gT - 24.5 = 0.5g
10T - 24.5 = 5
10T = 29.5
T = 2.95 s

Substitute T = 2.95 s in equation (1)
H = 0.5gT^2
= 0.5 * 10 * (2.95)^2
= 43.5 m

Height of the tower is 43.5 m

[Note: Actual Height of the tower will slightly differ from 43.5 m because I took g = 10 m/s^2. If this is not your answer take g = 9.8 m/s^2 and follow the same steps