science
posted by Pankaj kumar suman on .
A boy standing on top a building with a height of 500m throws a ball vertically upwards. The balls take 40s to reach to the ground. Neglecting the height of the boy throwing the ball, determine the velocity of the ball.

0 = .5 g (40^2) + Vo(40) + 500
solve for Vo (the throwing velocity)
Vo / g is the time to max height
40  (Vo / g) is the free fall time
(40 * g)  Vo is the impact velocity