A quarterback passes a football to a receiver on a windless day. Why are the initial horizontal speed (just as it leaves the quarterback's hand) and the final horizontal speed (just before it's caught) the same? You may ignore the effects of air friction.
A. Gravity pulls on the ball during its flight.
B. The vertical speed increases during the ball's flight.
C. There is no acceleration in the horizontal (or x) direction.
D. Actually, they're not the same.