A ball is projected vertically upward from the ground with a speed of 30m/s. A balcony is situated at a height of 40m above the ground. Neglect air resistance and take g=9.8m/s2.
(i) Calculate the maximum height reached by the ball above the ground.
(ii) Determine the times at which the ball passes the level of the balcony, once on the way up and again on the way down.
(iii) Find the velocity of the ball at the instant it crosses the balcony while descending.