A child stands on the edge of the cliff 10 m above the ground and throws a stone horizontally with an initial speed of 5 m s – 1 . Neglecting the air resistance, the speed with which the stone hits the ground will be _____ m s – 1 (given, g = 10 m s – 2 ).

Step-by-step solution

Given here, u = 5   m   s - 1 ,   h = 10   m Using v y 2 = u y 2 + 2 g h in vertical direction, we have the velocity of stone in vertical direction as v y = 2 g h = 200   m   s - 1 (since, u y = 0 ). The final velocity along the horizontal direction is the same as the initial horizontal velocity as there is no acceleration along the x-axis. The speed with which the stone hits the ground is v n e t = v x 2 + v y 2 = 25 + 200 = 15   m   s - 1