A stone is dropped from rest from the roof of a 100-m high building; 2.00 s after that, a second stone is thrown straight down with initial speed v0, and the second stone passes the first stone 21.6 m above ground.
(a) When are the stones at the same height?
(b) What was the initial speed, v0, of the second stone, in m/s?
(c) What are the speeds of the two stones, in m/s, just before they hit the ground?