Question

A car moving at 48.326 mph approaches an intersection and the driver observes the light go yellow. The driver's reaction time is 0.189 s. If the car can brake at a maximum acceleration of --2.511 m/s2, what is the minimum stopping distance in feet?

Answer 1

here, for the initial speed

u = 48.326 mph = 21.6 m/s

for the maximum acceleration , a = -2.511 m/s^2

for the minimum stopping distance

minimum stopping distance = 21.6 * 0.189 + 21.6^2/(2 * 2.511)

minimum stopping distance = 97 m

the minimum stopping distance is 97 m