Vo = 45,000m/3600s = 12.5 m/s.
If she tries to stop:
V^2 = Vo^2 + 2a*d.
0 = 12.5^2 - 2*5.8*d.
11.6d = 156.25, d = 13.5 m. To stop. Therefore, she should stop the car.
A person driving her car at 45km/h approaches an intersection just as the traffic light turns yellow. She knew that the yellow light lasts only 2s before turning red,and shi is 28m away from the near side of the intersection.
Should she try to stop,or should she speed up to cross the intersection before the light turns red? The intersection is 15m wide. Her car's maximum deceleration is -5.8m/s2,whereas it can accelerate from 45km/h to 65km/h in 6s. Ignore the length of her car and her reaction time
1 answer