Physics uses a standard nomenclature, which is different from the one used in most math classes. In physics, a particular variable name, and often the case of the variable (lowercase or capitalized), means a very specific thing.

Interactive exercise. Assistance may be required. Move your mouse over each of the following variables to see how scientists define it.

In addition to the standard nomenclature, physicists use subscripts to indicate what condition applies to the variable of interest. For example, the subscript "i" indicates the initial condition of the variable, and the subscript "f" indicates the final condition of the variable.

The study of motion using equations is known as kinematics. Physicists want to know details such as how fast an object is going after a given time interval rather than just the fact that the object moved. To describe the motion with greater detail, physicists use several kinematic equations, which describe motion.