You are travelling at 40 km/h. The braking distance for evasive braking is approximately 8 metres. How long is the braking distance at 50 km/h given otherwise the same conditions?

You answered correctly. The braking distance does not increase linearly with speed; it increases with the square of the speed. This means that if your speed increases from 40 km/h to 50 km/h, your braking distance increases more significantly than the speed change alone.

For example, if the braking distance at 40 km/h is about 8 meters, at 50 km/h it becomes (50²/40²) times longer. That calculation gives approximately 12.5 meters, which matches the correct answer. Always remember: higher speed means much longer braking distances, especially in emergency situations. This is an important principle for judging stopping distances while driving.