Final answer:
The average acceleration when velocity increases from 0 to 20 m/s over 10 seconds is 2 m/s², which is answer b.
Step-by-step explanation:
To calculate the average acceleration over a time interval, you can use the formula a = ∆v / ∆t, where ∆v is the change in velocity and ∆t is the change in time. In this example, the velocity increases from 0 to 20 m/s over 10 seconds. Therefore, the average acceleration is a = (20 m/s - 0 m/s) / 10 s = 2 m/s². So, the correct answer is b. 2 m/s².