# Average Velocity

The average velocity of an object is its total displacement divided by the total time taken. In other words, it is the rate at which an object changes its position from one place to another. Average velocity is a vector quantity. The SI unit is meters per second. However, any distance unit per any time unit can be used when necessary, such as miles per hour (mph) or kilometer per hour (kmph).

## Calculating Average Velocity

Calculating this velocity is a simple task. We need to divide the total displacement by the total time elapsed:

$\bar{v}=\frac{\Delta x}{\Delta t}=\frac{x_{f}-x_{0}}{t_{f}-t_{0}}$,

Where, $\Delta V$  is the average velocity,

$\Delta x$ is the displacement,

$\Delta t$ is the total time,

$^{x_{f}}$ and $^{x_{0}}$ are the initial position and the final position,

$^{t_{f}}$ and $^{t_{0}}$ are the starting time and the ending time.

If we take the starting time to be zero, the formula becomes:

$\bar{v}=\frac{\Delta x}{t}$

### Difference between Average Speed and Average Velocity:

• Average speed is defined as the total distance travelled by the time taken whereas average velocity is defined as the displacement by the time taken.
• Since speed is a scalar quantity, the average speed is also considered as a scalar quantity while velocity is a vector quantity. Therefore, the average velocity is a vector quantity.

It is enough to say that the speed of an object says, 25 m/s but on the other hand, the expression for the velocity of the same object will be 25 m/s, east (or any other direction).

For instance, if a remote-controlled car is racing from Point A to Point B and back to Point A, there is no overall displacement of the car. In that case, the speed of the car can be measured but not its velocity. If the same car moves from Point A to Point B and stays there, there is definite displacement in a certain direction. It can be measured in such cases. In simpler words, average velocity is just the average speed with a direction.

Stay tuned to BYJU’S and learn more about calculating average velocity and its relationship with speed through engaging video lectures.