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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?
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Solution

Diameter, d = 200 m, r = `d/2` 100 m
Time for one round = 40 s
Distance travelled in 2 minutes and 20 s
(2 × 60 + 20 = 140 s)
= `140/40`
= 3.5 rounds
Distance travelled = Circumference of the circle × 3.5
= 2πr × 3.5
= `2 xx 22/7 xx 100 xx 3.5`
= 2200 m
Displacement after 3.5 rounds
= diameter of the track
= 200 m
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