PROJECTILE MOTION
In general, an object that moves near the surface of the earth will not follow a
straight-line path; think of a baseball hit by a bat, a golf ball struck by a club, or a
tennis ball hit from the baseline. If we launch an object at an angle other than
straight upward, and consider only the effect of acceleration due to gravity, then the
object will travel along a parabolic trajectory.
The force of gravity causes an object to fall but does not affect the object’s
horizontal motion. To simplify the analysis of parabolic motion, we analyze the
horizontal and vertical motions separately, using the Big Five. This is the key to
doing projectile motion problems. Calling down the negative direction, we have