John runs 120 meters in 10 seconds and then runs back to where he started in another 10 seconds. Which statement is true? Remember: speed and velocity mean the same thing. Acceleration is a change is speed over a change in time.

B

Explanation:

A. His speed is 0 m/s

B. His velocity is 12 m/s

C. His velocity is 0 m/s

D. His acceleration is 12 m/s

Total distance traveled by John = 120 + 120 = 240 meters

Total time taken by John to cover the distance = 10 + 10 = 20 s

Average speed of John = total distance traveled/total time taken

      = 240/20 = 12 m/s

Hence, the average speed/velocity of John throughout the journey is 12 m/s.

The correct option is B.