The graph given below shows the motion of four runners p, q, r, and s in a 5 km marathon. a) who ran fastest? explain your answer? b) how can we determine the speed of runner q from the graph? c) calculate average speed of runner r? d) plot a distance-time graph for uniform motion?

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As we can see from the graphical data,

The distance covered by all the four runners is the same 5 km.

Among the four athletes, Athlete P covers the distance in under three hours.

It is the minimum time taken among the four athletes.

Thus Athlete P covers the 5 km distance in the minimum amount of time.

We know that speed =

Since time taken for P is minimum, his speed is the maximum. P ran the fastest.

Time taken by Q = 4.5 hours.

Speed of Q =

                     =

                    = 1.1 km/ hr

Time taken by R = 6 hours.

Speed of R =

                     =

                    = 0.8 km/ hr