A car moves on a straight road. As the driver passes a point A on the road with a speed of 20 ms–1, he
notices an accident ahead at a point B. He immediately applies the brakes and the car moves with an
acceleration of ams–2, where a = – 6 and t s is the time after passing A. When t = 4, the car passes
the accident at B. The car then moves with a constant acceleration of 2 ms–2 until the original speed of
20 ms–1 is regained at a point C. Find
(i) the speed of the car at B, [4]
(ii) the distance AB, [3]
(iii) the time taken for the car to travel from B to C. [2]
Sketch the velocity-time graph for the journey from A to C.