A stone is projected from the ground with speed 40ms−1 at an angle of 45∘ to the horizontal. Use g=9.8ms−2.
(i) Find the maximum height attained by the stone.
(ii) Determine the time(s) after projection at which the stone is at one–quarter of its maximum height.
(iii) Show that the sum of the two times obtained in part (ii) is equal to the total time of flight.