Answer to Question #257076 in Physics for dwal

Question

You are driving at the speed of 27.7 m/s (61.9764 mph) when suddenly the car in front of you (previously traveling at the same speed) brakes and begins to slow down with the largest deceleration possible without skidding. Considering an average human reaction, you press your brakes 0.436 s later. You also brake and decelerate as rapidly as possible without skidding. Assume that the coefficient of static friction is 0.911 between both cars’ wheels and the road. The acceleration of gravity is 9.8 m/s 2 . Calculate the acceleration of the car in front of you when it brakes.

Answer 1

Apply Newton's second law:

$$ma=\mu mg,\\\space\\ a=\mu g=0.911·9.8=8.93\text{ m/s}^2.$$