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

Explanation

Diameter of circular track (D) = 200m Radius of circular track ( r) = 200/2 = 100m
Time taken by the athlete for one round (t) = 40s. Distance covered by the Athlete in one round (s) = `2 pi r`
`=2xx ((22)/(7)) xx 100`
Speed of the athlete (v) = Distance/Time
`=(2 xx 2200)//(7 xx 40)`
`=4400//7 xx 40`
Therefore, distance covered in 140s = Speed `xx` Time
`=4400//(7 xx 40) xx (2xx 60 + 20)`
`=4400//(7 xx 40) xx 140`
`=4400 xx 140//7xx 40`
= 2200m
Number of round in 40s= 1 round
Number of round in 140s = `140//40 = 3^(½)` round
After taking start from position x, the athlete will be at position y
After `3^(½)` rounds as shown in figure.

Hence, Displacement of the athlete with respect to initial position at x-xy
=Diameter of circular track
=200m