A person on the top of a roof of a building (100 m) drops a ball. After 2s passed, a person who stands at the base of the same building throws a separate ball in the upward direction with a speed of 20 m/s. Assumes the two balls are traveling on the same vertical path. Will the two balls collide with each other? If so, what are their velocities as they collide with each other?

A person on the top of a roof of a building (100 m) drops a ball. After 2s passed, a person who stands at the base of the same building throws a separate ball in the upward direction with a speed of 20 m/s. Assumes the two balls are traveling on the same vertical path. Will the two balls collide with each other? If so, what are their velocities as they collide with each other?