Car A is traveling at 40 mi/h when it enters a 30 mi/h speed zone. The driver of

[James]

car A decelerates at a rate? of 16 ft/s2 until reaching a speed of 30 mi/h, which she then maintains. When car B, which is initially 60 ft behind car A and traveling at a constant speed of 45 mi/h, enters the speed zone, its driver decelerates at a rate of 20 ft/s2 until reaching a speed of 28 mi/h. Knowing that the driver of car B maintains a speed of 28 mi/h, determine (a) the closest that car B comes to car A (b) the time at which car A is 70 ft in front of car B