Publisher Summary This chapter provides an overview of particle kinematics. Kinematics is the branch of mechanics that describes the motion of physical bodies. It is distinguished from dynamics, which considers relationships between the motions of physical bodies and the forces (pushes or pulls) that are associated with those motions. The chapter also discusses models of physical bodies that may be considered mathematical points for the purpose of mathematical and physical analyses. A physical body may be regarded as a particle when only its translational motion is being considered, that is, when any vibrations or rotations of the body are of no consequence to the problem at hand. Large or small bodies may be treated as particles. The earth in its orbit or an automobile moving along a highway may each be thought of as a particle, provided the interest lies in its translational motion only. Perhaps the simplest example of kinematics is the motion of a particle constrained to move along a straight line. The speed of the particle at any instant is how fast the particle is moving at that instant. Its speed at a given instant is equal to the distance the particle would traverse each second if it proceeded at the rate it is moving at the given instant.