Question

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

Answer 1

Displacement is the shortest distance possible between initial and final position.

As the athlete is in circular motion , displacement is zero. [ THis is because , the initial and final position is the same ]

Distance covered in 1 round = Circumference of the circle

Circumference of the circle = 2πr

Diameter = 200 m

Radius = 100 m

Distance covered in 1 round[ 40 sec ] = 2 × 22/7 × 100 = 628.57 m

Distance covered in 1 sec = 628.57 ÷ 40 = 15.71 m

2min 20 sec = 140 sec

Distance covered in 140 sec = 15.71 × 140 = 2199.4 m

Answer 2

Answer:

Explanation:

Given :-

Diameter of circular track = 200 m

Radius, r = 200/2 = 100 m

Time taken by athlete to complete one round = 40 seconds.

To Find :-

Distance covered = ??

Displacement = ??

Formula to be used :-

Speed = Distance/Time

Circumference of circle = 2πr

Solution :-

Distance covered by athlete = 2πr

= 2 × 22/7 × 100

Now, Speed = Distance/Time

= 2 × 2200/7 × 40

= 4400/7 × 40

Now distance covered in 140 seconds,

= 4400/7 × 40 × 140

= 4400 × 140/7 × 40

= 2200 m

Hence, distance covered will be 2200 m.

And Displacement will be 200 m.