at height h directly above the first ball is dropped from rest.
a. At what height above the ground do the balls collide? Your answer will be a symbolic expression in terms of v0, h, and g .
b.What is the maximum value of h for which a collision occurs before the first ball falls back to the ground?
c.For what value of h does the collision occur at the instant when the first ball is at its highest point?
Express your answer in terms of the variable v0 and appropriate constants.