Question

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 min 20 sec?

Answer 1

An athlete will cover 2198 m distance in 2 min 20 sec and displacement at the end of 2 min 20 sec will be 200 m.

Diameter of circular track= 200 m

Radius of circular track= 100 m

Distance covered in one round of circular track= 2πr = 2 x 3.14 x 100 = 628 m

40 s time was taken to cover 628 m distance  

In 1 s time distance will be covered= 628/40 = 15.7 m

So 140 s time distance will be covered= 15.7 x 140 = 2198 m

Total 2198 m distance will be covered in 2 min 20 sec.

Displacement will be 200 m at the end of 2 min 20 sec because in 2 min 20 sec athlete will be at just opposite point from starting i. e. diameter of circular track.