Speed, distance & stopping distance

Near Heiloo you first drive 50 km/h, then you accelerate to 100 km/h on the same road. You want to stay at least 2 seconds behind the vehicle ahead the whole time. Roughly how many metres is that at both speeds?

Explanation

False — you make the distance four times as large. The 2-second distance is time times speed: twice as fast is twice as many metres, so 55 m at 100 km/h, not 110 m. Book p.123.