Assume you are driving a car at a constant speed of 75.0 km/h. Suddenly you see a deer standing on the highway and you must put on the brakes. Your reaction time (time elapsed between the moment you see the deer and your foot hitting the brakes) is 0.116 sec. The brakes provide an acceleration of -5.4 m/s2. Find the distance (in m) the car travels (at 75.0 km/h) during your reaction time. Calculate the total distance (in m) traveled by the car before stopping.

1 answer

75 km/hr = 20.833 m/s
so, at 75km/hr, the car travels

20.833 * 0.116 m

Then, it takes 20.833/5.4 seconds to stop, and the distance traveled while braking is

20.833t - 2.7t^2

where t is the above stopping time.