Mechanics is the study of the physical laws that describe the motion of objects. When studying moving objects, it is often useful to simplify their motion by treating them as single particles. In this context, a particle is defined as a small object whose microscopic structure is irrelevant to its motion. The fundamental concepts of mechanics are thus all introduced using this simplification, from kinematics, the branch of mechanics that quantitatively describes how a particle moves, to dynamics, which studies motion and its causes.

The simplest case of motion is treated by considering the rectilinear or translational motion of a particle along an axis. This type of motion is described using the following quantities: displacement, speed, velocity and acceleration. The position of a particle in space is a vector quantity because it has both magnitude and direction since it is specified according to a...