Question

A boy throws a ball vertically up. It returns the ground after seconds. Find the  maximum height reached by the ball.​

Answer 1

If he throws the ball with speed V then (vertical speed)

V / g is the time to reach maximum height (V2 - V1) / a

The total time to again reach the ground is then

T = 2 V / g

H = 1/2 g t^2 where t = V / g

H = 1/2 g (V / g)^2 = V^2 / (2 g)

This is the familiar formula

V = (2 g H)^1/2 for the initial upwards speed