Question

A stone is projected from a horizontal plane. It attains maximum height ‘H’ and strikes a stationary smooth wall and falls on the ground vertically below the maximum height. Assume the collision to be elastic, the height of the point onthe wall where stone will strike is-

• A. H/2
• B. H/4
• C. 3H/4
• D. None of these

Answer 1

Answer: (C)

3H/4

Answer 2

H = $\frac{1}{2}$g (2t)² = 2gt^{2 . . . .} (1)

h = H$- \frac{1}{2}$ gt^{2 . . . .} (2)

By (1) and (2)

h = H$- \frac{H}{4} = \frac{3H}{4}$