Starting from rest, a bus increases speed at constant acceleration a1, then travels at constant speed vm and finally brakes to a stop at constant acceleration a2 (a2 < 0). It took 4 minutes to travel the 2 miles between stop C and stop D and then 3 minutes to go the 1.4 miles between stop D and stop E.
a. Sketch the graph of the velocity v as a function of time 0 ≤ t ≤ 7.
b. Find the maximum speed vm.
c. If a1 = -a2 = a, evaluate a.