A ball is thrown vertically upward from the roof of a building 25m high with an initial speed of 15ms−1. It eventually falls to the ground at the base of the building. Ignore air resistance.
(i) Calculate the time taken for the ball to reach its highest point.
(ii) Find the maximum height above the roof that the ball attains.
(iii) Determine the total time elapsed from the instant of projection until the ball strikes the ground.