Question

an athlete completes one round of circular track of diameter 200m in 40s.what will be the distance covered and displacement at the end of 2m 20s

Answer 1

Distance = 2πr given that it is a circle.

Distance in 40 s = 200 × 3.142 = 628.4m

In 2m 2 s = 122 s will be

(122 / 40) × 628.4 = 1916.62

The displacement

Here we consider the revolution.

122/40 = 3.05 revolutions.

We will consider 0.05 since in the 3 complete revolutions the displacement is 0.

0.05 × 628.4 = 31.42 m

Answer 2

HEY!!

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⏺️An athlete takes 40 sec for 200 m diameter circular track.

⏺️It means he covers 2 pi R distance (2R = 200 m) in 40 sec,

⏺️⏺️Then,

⏺️In 2 min 20 sec=140 sec, he moves{2 pi R)/40} x140 = 7 pi R

⏺️Therefore the total distance travelled is given by

⏺️d = 7 pi R

⏺️7 x(22/7)x100

⏺️⏺️ 2200m

⏺️Displacement = Shortest path travelled by any object.

⏺️So after 7 pi R it'll be at point diametrically opposite point of its initial position.

⏩Then displacement = 2R =200m.