In heavy rush-hour traffic you drive in a straight line at 12 m/s for 1.5 minutes, then you have to stop for 3.5 minutes, and finally you drive at 15 m/s for another 2.5 minutes.

(a) Plot a position versus-time graph for this motion. Your plot should extend from t = 0 to t = 7.5 minutes.

(b) Use your plot from part (a) to calculate the average velocity between t = 0 and t = 7.5 minutes.