Question

An athlete completes one round of a circular round of a circular track of diameter 200m in 40s. What will be the distance covered and the displacement at the end of 2 mins 20s? With steps plse..

Answer 1

Diameter = 200 m
Radius = 100 m

Circumference = 2πr = 2 x 100π = 200π m in 40 secs
2 min 20 s = 120 + 20 = 140 secs
Distance covered in 140 secs = 200π x 140 = 28000π m = 28π km

Displacement = Diameter of the circle = 200 m

Hope This Helps You!

Answer 2

"Distance covered in 140 sec is 2199.4 m

Solution:

We know that the displacement is the smallest distance possible between initial and final position.

It is known that the athlete is in circular motion. So displacement is zero. (Due to the initial and final point are same)

Distance covered in 1 round = Circumference of the circle

Circumference of the circle $= 2 \pi \mathrm{r}$

Diameter = 200 m

Radius = 100 m

Distance covered in 1 round $[ 40 sec ] =2\quad \times \quad \frac { 22 }{ 7 } \quad \times \quad 100\quad =\quad 628.57\quad { m }$

Distance covered in 1 sec $=\frac { 628.57 }{ 40 } \quad =\quad 15.71{ \quad m }$

$2min 20 sec = 140 sec =\quad 15.71\quad \times \quad 140\quad =\quad 2199.4{ \quad m }$"