I just need ideas on how i can estimate the height of a building by using only a tennis ball and a stop watch. I can only measure it by being on the ground level.

2 answers

Can you throw the ball up as high as the roof? If so, time the ball from the top of the arc to when it hits ground

h=1/2 g t^2
A tennis ball of mass m = 0.058 kg and speed v = 26 m/s strikes a wall at a 45^\circ angle and rebounds with the same speed at 45^\circ .

What is the magnitude of the impulse given to the ball?