Kinematics is the description of motion without concern of the cause. By now, you should be familiar with the set of equations that describe motion using descriptors such as displacement, velocity and acceleration, often as functions of time. These equations developed for one dimensional motion all make the assumption that the accelerations are constant. While there are many instances where accelerations are not constant, these equations are extremely useful when accelerations do in fact remain fairly constant, or when time intervals are short enough to warrant that assumption. The power behind these relationships, is in the ability to make reliable predictions of motion. After mastering kinematics in one dimension, we can apply the same set of equations for two or more dimensions. Let's consider a classically important example: projectiles