Question

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?

Answer 1

Answer:-

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 = $\frac{Distance}{Time}  $

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 = $\frac{Distance}{Time taken by Q}$

                     = $\frac{5km}{4.5hour}$

                    = 1.1 km/ hr

Time taken by R = 6 hours.

Speed of R = $\frac{Distance}{Time taken by R}$

                     = $\frac{5km}{6hour}$

                    = 0.8 km/ hr