An automobile travels along a straight road in three stages:
1. It accelerates uniformly from rest to 25ms−1 in 5s.
2. It maintains this speed for the next 10s.
3. It then decelerates uniformly to rest in a further 5s.
Taking the starting point as the origin and time t=0 at the instant the automobile begins to move, answer the following:
a. (i) Draw the velocity–time graph for the complete 20s journey.
b. (ii) Using the graph drawn in part (i), sketch the corresponding displacement–time graph for the same interval, marking key points and slopes.