Question

Assume that the brakes in your car create a constant deceleration of 3.9 m/s^2, regardless of how fast you are driving.

If you double your driving speed from 18 m/s to 36 m/s, does the time required to come to a stop increase by a factor of two or a factor of four? Explain.

Answer 1

The time required to come to a stop will increase by a factor of four. This is because the acceleration is constant, and the stopping distance is proportional to the square of the speed, so doubling the speed quadruples the stopping distance.