3 A pair of cameras records the time that it takes a car on a motorway to travel a distance of 2000 metres. A car passes the first camera whilst travelling at \(32 \mathrm {~ms} ^ { - 1 }\). The car continues at this speed for 12.5 seconds and then decelerates uniformly until it passes the second camera when its speed has decreased to \(18 \mathrm {~ms} ^ { - 1 }\).
- Calculate the distance travelled by the car in the first 12.5 seconds.
- Find the time for which the car is decelerating.
- Sketch a speed-time graph for the car on this 2000-metre stretch of motorway.
- Find the average speed of the car on this 2000-metre stretch of motorway.