Question

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

Answer 1

Hey!

Diameter of the circular track (d) = 200m
Hence, radius of the track (r) = d/2 = 100m

Time taken to complete one round = 40s
Total time taken = 2min 20s = 140s

Length if the circular track = 2πr
= 2× 22/7 ×100 m
= 4400/7 m

Therefore, distance travelled in 40s = 4400/7m
Distance travelled in 140s = 4400/7 × 140/40 m
= 2200m

Number of rounds in 2200m = 2200×7/4400
=3•5

Since in one complete rotation the displacement is zero as the athlete reaches the same position, displacement in 3•5 rounds will be equal to the diameter of the track as the athlete will be totally opposite the starting point.

Displacement = Diameter = 200m

Distance = 2200m
Displacement = 200m
[at the end of 2 min 20s]

Thank you!