A stone is projected vertically downward from the roof of a 45m high building with an initial speed of 4ms−1. Take g=9.8ms−2.
(i) Calculate the time taken by the stone to reach the ground.
(ii) Find the speed with which it strikes the ground.
(iii) Suppose another identical stone is dropped (released from rest) from the same point at the same instant. Just before the first stone hits the ground, by how much distance will it be ahead of the second stone?