Alex climbs to the top of a tall tree while his friend gary waits on the ground below. alex throws down a ball at 8 m/s from 50 m above the ground at the same time gary throws a ball up. at what speed must gary throw a ball up in order for the two balls to cross paths 25 m above the ground? the starting height of the ball thrown upward is 1.5 m above the ground. ignore the effects of air resistance. whats the answer in m/s?