Your 2000 kg car is going 40 m/s on the highway when you see a police car up ahead. You apply the maximum 10000 N of brake force to slow your car down to the speed limit of 30 m/s. How many seconds will it take you to get down to the speed limit?
a=(30-40)/time
F=ma
10000=2000*aFromAbove
solve for time t.