1. Determine the change in velocity:

* The train's initial velocity (v1) is 25 m/s.

* The train's final velocity (v2) is 10 m/s.

* Change in velocity (Δv) = v2 - v1 = 10 m/s - 25 m/s = -15 m/s

* The negative sign indicates the train is slowing down.

2. Calculate the acceleration:

* Acceleration (a) is the rate of change of velocity over time.

* Time (t) = 240 s

* Acceleration (a) = Δv / t = -15 m/s / 240 s = -0.0625 m/s²

Description:

The train is undergoing deceleration (negative acceleration) of 0.0625 m/s². This means its speed is decreasing by 0.0625 meters per second every second.