The question is:
Ball A is dropped from the top of a building of height h, and simultaneously Ball B is thrown vertically upward. If the two balls collid at height h/3, what is the initial velocity of Ball B?
The answer they are looking for is:
Vinitial = 1/2*sqrt(3gh)
But I have no idea how to get there. The closest I can get using the formulas I know is:
Vinitial = Vfinal - sqrt(2gh/3)
(g refers to the acceleration of gravity, -9.81m/s)