A stone is thrown vertically upward from the edge of a cliff that is 50m high. The initial speed of the stone is 20m s−1 upward. Take the downward direction as positive and g=9.8m s−2.
(i) Calculate the greatest height above the cliff edge that the stone reaches.
(ii) Determine the total time taken by the stone to hit the ground at the foot of the cliff.
(iii) Find the speed with which the stone strikes the ground.