The basic notions of classical physics concern particles moving in straight lines, or linear motion. The concepts of linear motion are usually grouped into two categories, kinematics and dynamics. Kinematics deals with predicting the position of a particle if its position, velocity, and acceleration at some reference time (usually set to be t =0) is known. Velocity is the rate of change of position with respect to time, and acceleration is the rate of change of velocity with respect to time. The two kinematical equations are, for constant acceleration: v(t) = v + at, and x(t) = x + vt + 1/2 at2 , where x is the position, v is the velocity (the subscripted v indicates the velocity at the start or origin), a is the acceleration, and t is understood as the change in time.

Dynamics deals with how kinematical quantities such as velocity and acceleration react to forces. The...