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

Heya,

Answer:-

Here we have,

Diameter = 200 m, therefore, radius = 200m/2 = 100 m

Time of one rotation = 40s

Time after 2m20s = 2 x 60s + 20s = 140s

Distance after 140 s = ?

We know that, velocity along a circular path =Circumference/time

⇒v=2πr40s⇒v=2πr40s

⇒v=2×3.14×100m40s⇒v=2×3.14×100m40s

⇒v=628m40s⇒v=628m40s

⇒v=15.7m/s⇒v=15.7m/s

(a) Distance after 140s

We know that,distance=velocity ×time

⇒ distance=15.7m/s ×140 s = 2198 m

(b) Displacement after 2 m 20 s i.e. in 140 s

Since,rotatin in 40 s=1

Therefore, rotation in 1s=1/40

∴ rotation in 140s=140×140=3.5140s=140×140=3.5

Therefore, in 3.5 rotations athlete will be just at the opposite side of the circular track, i.e. at a distance equal to the diameter of the circular track which is equal to 200 m.

Therefore,

Distance covered in 2 m 20 s = 2198 m

And, displacement after 2 m 20 s = 200m

Thank you for asking such a nice question,..

Hope helped!!