When the ball reaches the highest point, its velocity will be zero. So final velocity is v=0m/s Here, the time to reach highest point is equal to time to hit ground from highest point. Consider upward motion, the acceleration of the ball is a=−g=−9.8m/s 2 (minus for motion opposite to gravity) If t be the required time. Using v=u+at, 0=25+(−9.8)t ⟹ t=2.5s Thus the ball hits the ground after 2.5 seconds after reaching its highest point.
