In physics, we say that a body has acceleration when there is a change in the velocity vector, either in magnitude or direction. In this section, we are going to study the concept of average acceleration, which represent the variation in velocity that, on average, takes place in a time interval.

## Average Acceleration

**Average acceleration** between two points *P _{1}* and

*P*is defined as the

_{2}*ratio*of the

**and**

*variation of the velocity**used to complete the motion between both points:*

**the time**where:

- ${\overrightarrow{a}}_{a}$ : Is
**average acceleration**of the body - ${\overrightarrow{v}}_{1}$ ,${\overrightarrow{v}}_{2}$ :
*Velocity vectors*of points*P*and_{1}*P*respectively_{2} *t*,_{1}*t*: Initial and final_{2}*times*respectively- $\u2206\overrightarrow{v}$ :
**Variation of the velocity**between the initial and final points*P*and_{1}*P*_{2} - $\u2206t$ :
*Time*spent in completing the motion between*P*and_{1}*P*_{2}

Additionally, the **average acceleration vector** satisfies the following:

- The
is [a**dimensional equation of the average acceleration**_{a}] = [LT^{-2]} - The
of the acceleration is*unit of measurement in the International System (S.I.)***meter per second squared (m/s**. A body with a 1 m/s^{2})^{2}acceleration changes its velocity by 1 meter/second every second - Its magnitude (the "size" of the vector) is equal to the magnitude of the velocity variation vector divided by the elapsed time
- Its direction is the same as the direction of the velocity variation vector

It is important to remember that motion, which is colloquially called *"braking"*, is also considered accelerated motion in physics, because in the end, the velocity vector is changing (specifically deceasing its magnitude).