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Mark scheme (whole question; this part is marked with the orange bar)
Examiner's comment
In the second part, most candidates connected the area under the graph to the distance of 15 km travelled, although some forgot to change km into m or converted it wrongly. Some chose to use the formula for the area of a trapezium directly, others divided the area into two triangles and a rectangle and a small number used a rectangle with two triangles subtracted. A significant number of candidates chose to solve the problem by using an explicit verification method, using t = 40 and the information given about the acceleration and deceleration times and the total time to show that the distance travelled was 15000 m but lost the final mark if they did not say that this was equal to 15 km. The vast majority of candidates scored the mark in part
Common mistakes
- total area under the graph = 15000 m (convert km to m)
- ½(700 + 700 − 5t) × 25 = 15000 gives t = 40
- a single suvat for the whole journey scores 0
- verification must conclude = 15 km