A bus leaves a bus-stop at time t = 0 and travels along a horizontal road until it reaches a second bus-stop. Fig. 7.1 is the distance-time graph for the bus between t = 0 and t = 60s. [Figure 7.1] The road on which the bus is travelling is straight except for a short, curved section. The bus travels around this circular curve between t = 21 s and t = 24 s.

1. (a)Describe how the motion of the bus between t = 0 and t = 10s differs from its motion between t = 35s and t = 40 s.[3]
2. (b)Determine:
3. (b)(i)the maximum speed of the bus during these 60s maximum speed =[3]
4. (b)(ii)the average speed of the bus between leaving the first bus-stop and arriving at the second bus-stop. average speed =[2]
5. (c)(i)State how velocity differs from speed.[1]
6. (c)(ii)There are three periods during the 60s when there is a non-zero resultant force acting on the bus. Complete the statements to indicate these three time periods and state the direction of the resultant force in that period. 1. Between t = .......... and t = .......... the direction of the resultant force is .......... 2. Between t = .......... and t = .......... the direction of the resultant force is .......... 3. Between t = .......... and t = .......... the direction of the resultant force is ..........[4]
7. (d)During the journey, the air resistance acting on the bus varies.
8. (d)(i)State why the air resistance changes during the journey.[1]
9. (d)(ii)On Fig. 7.1, mark and label with an M a time when the air resistance is a maximum value.[1]

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