posted by mark matat .
A ball is thrown from the top of a building with an initial velocity of 30m/s straight upward, at an initial height of 50m above the ground. The ball just misses the edge of the roof on is way down and hits the ground. Determine: a) time needed for ball to reach max height. B)the max height. C) time needed for ball to hit ground. D) velocity and diplacement ( magnitude and direction) of the ball at t=sec( measured from beginning. Please explain step by step