A ball is projected vertically upward from the top of a tower 45m high with an initial speed of 15ms−1. Neglect air resistance and take g=10ms−2 directed downward.
(i) Determine the greatest height above the ground that the ball attains during its motion.
(ii) Calculate the total time elapsed from the instant of projection until the ball strikes the ground at the foot of the tower.
(iii) Find the magnitude of the velocity with which the ball hits the ground.