Question

An athlete completes one round of a circular track of diameter 200 m in 40 s. What will be the distance covered and the displacement at the end of 2 minutes 20 s?

Answer 1

Length AB = 200m = 2R
Time taken to complete one round = 40 sec
Let the starting point be A
In 140 sec or 2 min 20 sec number of rounds completed = $\frac{140}{40}=3.5$
Distance travelled = $3.5\times (2\times \frac{22}{7}\times R)=3.5\times 2\times \frac{22}{7}\times 100m=2200m$ (approx.)
Displacement refers to change in position from the starting point. The final point is B
As after 3.5 revolutions (starting from A) the athlete will be at B.
Displacement = 200 m