Acceleration Calculation
Acceleration is the rate at which an object changes its velocity. It is measured in meters per second squared (m/s²). To calculate acceleration, we need to know the initial velocity, final velocity, and time taken.

Given Information
Initial Velocity (u) = 0 m/s (since the train started from rest)
Final Velocity (v) = 90 m/s
Time (t) = 1 minute = 60 seconds

Formula
Acceleration (a) = (v-u)/t

Calculation
a = (90-0)/60
a = 1.5 m/s²

Therefore, the acceleration of the train is 1.5 m/s².

Explanation
The given information tells us that the train starts from rest (u=0) and attains a velocity of 90 m/s in 60 seconds (t=60). We can use the formula for acceleration to find the rate at which the train's velocity changes.

From the formula, we can see that acceleration depends on the change in velocity and time taken. In this case, the change in velocity is 90 m/s (v=90) and the time taken is 60 seconds (t=60).

Substituting these values in the formula, we get an acceleration of 1.5 m/s². This means that the train's velocity increases by 1.5 m/s every second.

Acceleration is an important concept in physics as it helps us understand how objects move and change their velocity. It is also used in many real-world applications, such as designing cars, rockets, and roller coasters.