Final answer:
To solve projectile problems, you must analyze the motion in the vertical and horizontal directions separately. The components of the motion are independent and can be treated individually.
Step-by-step explanation:
To solve projectile problems, you must divide your information into two parts: the vertical motion and the horizontal motion.
To analyze the projectile motion, you break it into motions along perpendicular directions. The components of the motion are independent, so you can treat the vertical and horizontal motions separately.
By separating the motion into two independent one-dimensional motions, you can solve for the time of flight and other parameters of the projectile's motion.