A ball is thrown vertically upward with an initial speed of 25 m/s. Then, 1.8 s later, a stone is thrown straight up (from the same initial height as the ball) with an initial speed of 32.1 m/s .

Question

How far above the release point will the ball and stone pass each other? The acceleration of gravity is 9.8 m/s2 .
Answer in units of m.

Answer 1

x1 = 25(t) - 4.9t^2
x2 = 32.1 (t+1.8) - 4.9(t+1.8)^2
Set them equal to each other. Solve for t (note t=zero is a trivial solution), plug the t back into the originals.