When velocity changes by the same amount over each time period, the acceleration is constant.

Here's why:

* Acceleration is the rate of change of velocity over time.

* Constant acceleration means the velocity changes by the same amount in every equal time interval.

Example:

Imagine a car moving at 10 m/s. If its velocity increases to 20 m/s in 5 seconds, then to 30 m/s in another 5 seconds, and so on, the car is experiencing constant acceleration. The velocity is increasing by 10 m/s every 5 seconds.

Formula:

Acceleration (a) can be calculated using the formula:

a = (change in velocity (Δv)) / (time (Δt))

In the case of constant acceleration, the change in velocity (Δv) will be the same for each time interval (Δt).