Physics (AS & A Level) · Oct / Nov 2016 · Paper 12 · Question 10

In order that a train can stop safely, it will always pass a signal showing a yellow light before it reaches a signal showing a red light. Drivers apply the brake at the yellow light and this results in a uniform deceleration to stop exactly at the red light. The distance between the red and yellow lights is x. If the speed of the train is increased by 20%, without changing the deceleration of the train, what must be the minimum distance between the lights?

1. A1.20 x
2. B1.25 x
3. C1.44 x
4. D1.56 x

As printed in the paper