Question

an athlete completes one round of a circular track of dimeter 200 m in 40 sec what will be the distance covered and the displacement at the end of 2 minuter 20 seconds?​

Answer 1

★ GivEn :-

• An athlete completes one round of a circular track of dimeter 200 m in 40 sec.

★ To Find :-

• The distance covered and the displacement at the end of 2 minutes 20 seconds.

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★ Solution :-

The diameter of the circular track is = 200 m.

Then, the radius of the circular track would be,

= (200 ÷ 2 ) m = 100 m.

According to the given question,

the athlete completes one round of the circular track,

therefore, the distance covered will be 2πr m. ( r is radius of the track )

In 40 sec he covers one round.

So in ( 120 + 20 ) = 140 sec he will cover 3.5 rounds.

$\implies {\underline {\boxed {\pink {\sf{Distance = (3.5 \times 2 \times 3.14 \times 100 )\: m}}}}}$

$\implies {\underline {\boxed {\pink {\sf{ \therefore \: Distance = 2198 \: m}}}}}$

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Now, the shortest distance ie straight line distance between the initial position and final position of the body, alongwith direction is known as its displacement.

So after covering 3 complete rounds more 0.5 round left to cover. While covering 3 complete rounds the initial position and final position is same, so till then the displacement remains 0.

While covering the next 0.5 round, he covers a half round of the circular track.

$\implies {\underline {\boxed {\pink {\sf{ \therefore \: Displacement = 200 \: m}}}}}$

The diameter of the circular track is the shortest distance between his initial and final point.

Answer 2

Question

An athlete completes one round of a circular track of diameter 200m in 40 seconds what will be the distance covered and the displacement at end of 2 minutes 20 second ?

Answer

what is given ?

• it is given that the diameter is 200
• radius of the circular track (200/2=100m)

What we have to find ?

• we have to find here the distance covered and the displacement at the end of 2 minutes 20 second .

Solution

D = 200m (Diameter).

Radius = 100 m

In 40 sec he will cover one round .

Now,

the 35 rounds he will cover in 140 sec ( 120+20=140)

now to find the distance

we have to use the formula 2πr .

putting the formula in 2πr ,

3•5.2.3•14.100

=> 2198 m

so the distance covered is 2198 m and as the diameter is 200 so the displacement will also be 200 m .