1. A ball is dropped from rest from the top of a building of height h. At the same instant, a second ball is projected vertically upward from ground level, such that it has zero speed when it reaches the top of the building.
a. When do the two balls pass each other? Answer it in terms of h.
b. Which ball has greater speed when they are passing?
c. What is the height of the two balls when they are passing?