A stone falls from a cliff and travels 24.5 metres in the last second before it reaches the foot of the cliff. Find height of the cliff.

Explanation

Initial velocity of the stone u = 0, g = `9.8 m / /s^2` If n is the last second, then Distance covered in the nth second = 24.5 m
Using `24.5 = 9.8//2 (2n-1) or 2n-1 = 24.5//4.9 =5` or n = 3