Projectiles are objects launched with both horizontal and vertical components to their velocity. This section takes what was learned in 2D kinematics and helps quantify this movement. Some examples would be a baseball being thrown or a stuntman in a car driving off a cliff.
OpenStax has a rad trailer about projectile motion.
Read the BoxSand Introduction and watch the pre-lecture videos before doing the pre-lecture homework or attending class. If you have time, or would like more preparation, please read the OpenStax textbook and/or try the fundamental examples provided below.
Projectile motion is a special case of 2D kinematics, where the acceleration is constant and points down towards the Earth. It's free-fall in two dimensions. Since the acceleration points downward, using a standard coordinate system where the x-direction is along the horizontal and the y-direction is along the vertical, means that there is zero x-component to the acceleration. If an object is not accelerating in a given direction, then it maintains a constant speed along that direction, as denoted by the constant length of the VxVx component of the velocity vector in the physical representation below.
This is picture of an object undergoing projectile motion. The figure shows the object at various times in it's flight. There are vectors to represent the velocity, acceleration, and change in position for the motion
In the physical representation of an object in projectile motion, notice that the x-component of the velocity remains constant, while the y-component does not. The y-component of the velocity decreases on the way up, since vyvy points in the opposite direction of ayay and then on the way down the y-component increases, since both vyvy and ayay point in the same direction. If air resistance is negligible, the path of the motion is parabolic.
OpenStax covered projectile motion in section 3.4.
