For a projectile, describe the changes in the horizontal and vertical components of its velocity, when air resistance is negligible. Explain why a projectile moves equal distances horizontally in equal time intervals, when air resistance is negligible. Show an understanding of the independence of vertical and horizontal velocities of a projectile. Find the velocity of a projectile launched horizontally when a change in the vertical distance occurs. Find the maximum height and range of projectiles launched at an arbitrary angle.