Final answer:
The acceleration of the van is calculated by dividing the change in velocity, 14 m/s, by the time interval, 10 seconds, resulting in an acceleration of 1.4 m/s².
Step-by-step explanation:
To calculate the acceleration of a van that increased its speed from 31 m/s to 45 m/s in 10 seconds, we use the formula for average acceleration, which is the change in velocity ∆v divided by the time ∆t over which the change occurred: a = ∆v / ∆t. The change in velocity (∆v) is the final velocity minus the initial velocity, which in this case is 45 m/s - 31 m/s = 14 m/s. The time (∆t) is given as 10 seconds. So, the acceleration is computed as a = 14 m/s / 10 s = 1.4 m/s². Therefore, the correct answer is A. 1.4 m/s².