Halliday, Resnick & Walker — Motion Along a Straight Line: Problem 30

30 The brakes on your car can slow you at a rate of \(5.2 \text{ m/s}^2\). (a) If you are going \(146 \text{ km/h}\) and suddenly see a state trooper, what is the minimum time in which you can get your car under the \(90 \text{ km/h}\) speed limit? (The answer reveals the futility of braking to keep your high speed from being detected with a radar or laser gun.) (b) Graph \(x\) versus \(t\) and \(v\) versus \(t\) for such a slowing.