The Railroad Crossing (continued) 4. The car is traveling on the highway at an initial velocity of 45 mph (20 m/s) to the East. The driver sees the RR X-ing lights flashing and steps on the brakes, bringing the car to a complete stop in 80 m. a. What is the acceleration of the car while it is braking? b. How much time does it take for the car to stop? 5. After the train passes by, the car accelerates from 0-50 mph (22.2 m/s) in 5.5 s. a. What is the acceleration of the car while it is speeding up? b. What is the displacement of the car while it is speeding up? 6. After reaching 50 mph (22.2 m/s), the car continues driving at a constant speed. a. How much farther does the car have to drive to have traveled a total distance of 500 m from the point where it first started braking? (Hint: consider the stopping distance and the displacement while speeding up) a. How much time does it take for the car to travel that extra distance?