Average speed is defined as total distance divided by time. Speed is defined as the magnitude of the velocity vector. Consider a car completing 24 circuits (6 miles) around a track in 10 minutes. The car's average speed is then 60 miles per hour. However, the car's final position is the same as the initial position, so the change in position is 0 and the average velocity for the drive must also be 0. So it is possible for an object to have non-zero average speed and zero average velocity.
Acceleration is defined as the rate of change of velocity:
The vectors of velocity and acceleration may point in different directions. This quantity is considered over an interval and is thus an average value. Instantaneous acceleration is the acceleration at a single point in time and is given by the quantity
