Video narration
How can a ball move forward while it rises, then falls, all at the same time? When you throw it at an angle, describe its motion in a plane using two components: a horizontal and a vertical. These aren't two trips; they happen together to describe one ball. Across the ground, horizontal motion keeps moving forward at constant speed if we ignore air resistance. Vertically, gravity pulls downward: the ball rises, slows, reaches its highest point, then falls faster. At each moment, combine how far the ball has moved horizontally with how high it is vertically. Those positions give its trajectory-the curved path you see. The curved path is not one mysterious motion. It is horizontal motion combined with vertical motion under gravity. How does the ball move in two directions at once? By combining those two motions into one curved path.