일반물리학 1 — Motion Along a Straight Line: Problem 54

54 A stone is dropped into a river from a bridge 53.6 m above the water. Another stone is thrown vertically down 1.00 s after the first is dropped. The stones strike the water at the same time. (a) What is the initial speed of the second stone? (b) Plot velocity versus time on a graph for each stone, taking zero time as the instant the first stone is released.