2026 EVG P1 Q20

The diagram shows the speed–time graph of a lorry. The lorry starts from rest and accelerates uniformly to a speed of 15 m/s in 10 seconds. The lorry then travels at a constant speed for some time before it decelerates uniformly at \(0.75\text{ m/s}^2\) until it comes to rest.

The whole journey takes one minute.

1. Given that the speed after x seconds is v m/s, express v in terms of x.[1]
2. For how long does the lorry travel at the maximum speed?[2]
3. Calculate the total distance travelled by the lorry during this 1 minute journey.[2]