A ping pong ball is thrown horizontally out of a window 30m above the ground. If the initial velocity of the ball os 20.0 m/s, how far will the ball move horizontally before it hits the ground?

A change in the position of a body with respect to time relative to a reference point is motion.
Because there is no absolute point of reference, there is no true discernible absolute motion, and therefore, everything is said to be moving constantly.
Hope that helped =)