Halliday, Resnick & Walker — Motion Along a Straight Line: Problem 90

Braking, no reaction time. Modern cars with a computer system using radar can eliminate the normal reaction time for a driver to recognize an upcoming danger and apply the brakes. For example, the system can detect the sudden stopping of a car in front of a driver by using radar signals that travel at the speed of light. Rapid processing then can almost immediately activate the braking. For a car traveling at \( v = 31.3 \text{ m/s} \) (70 mi/h) and assuming a normal reaction time of 0.750 s, find the reduction in a car’s stopping distance with such a computer system.