2026 CCHMS P1 Q21

The diagram shows the speed-time graph of a train travelling from Town \(P\) to Town \(Q\). The train left Town \(P\) at 1000 hrs and accelerated at a constant rate before reaching a maximum speed of \(v\) km/h after 10 minutes. It then travels at a uniform speed for 45 minutes before decelerating at a uniform rate. The train arrived at town \(Q\) at 1100 hrs.

1. The area under the speed-time graph represents the distance travelled by the train. Given that the train travelled a total of 70 km, show that v = 80.[2]
2. Calculate the acceleration of the train during the first 10 minutes of its journey. Give your answer in km/h².[1]
3. Sketch the distance-time graph for the train during its journey from Town \(P\) to Town \(Q\).[2]