Atruck on a straight road starts from rest, accelerating at 2.00 m/s2 until it reaches a speed of 38.0 m/s. then the truck travels for 86.0 s at constant speed until the brakes are applied, stopping the truck in a uniform manner in an additional 5.00 s. (a) how long is the truck in motion? (b) what is the average velocity of the truck for the motion described? a car has an initial velocity vo when the driver sees an obstacle in the road in front of him. his reaction time is atr, and the braking acceleration of the car is a. (a) show that the total stopping distance is given by the formula below. remember that a is a 2. negative number. (vo)2 2a stopoatr.. (i) the yellow caution light on a traffic signal should stay on long enough to allow a driver to either pass through the intersection or safely stop before reaching the intersection. a car can stop if its distance from the intersection is greater than the stopping distance given by the same equation (i). if the car is less than this stopping distance from the intersection, the yellow light should stay on long enough to allow the car to pass entirely through the intersection. (b) show that the yellow light should stay on for a time interval given by the following, where t, is the driver's reaction time, vois the velocity of the car approaching the light at the speed limit, a is the braking acceleration, and s is the width of the intersection. tlight = + (ii) (c) as city traffic planner, you expect cars to approach an intersection 13.5 m (almost 45 ft.) wide with a speed of 61.5 km/h (approx.. 40 mi/h). be cautious and assume a reaction time of 1.10 s to allow for a driver's indecision. find the length of time the yellow light should remain on (in seconds). use a braking acceleration of-2.00 m/s2. use equation (it).