Question

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

Answer 1

Given:

Diameter of circular track = 200m = r = 100m

Time taken = 40 seconds

To find: Distance covered and displacement in 140 seconds (2 Min 20 seconds)

Solution:

Circumference of track =

Distance covered in one round:

                 = 2πr

                 = 2 * 22/7 * 100

                 = 628.571

Number of rounds:

                  = 140/4

                  = 35

Therefore, Total distance covered =

                  = 628.571 * 35

                  = 2200 meters

1. Therefore, Total distance covered by Athlete at the end of 2 min 20 seconds is 2200 meters or 2.2 Km.

2. Since the athlete returns to it's original position because the round is circular. Therefore, Displacement is 200.

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Explanation:

• In the given example, It is given that the athlete covers one round of circular track of diameter 200 meters in 40 seconds.

• To find the distance covered by athlete in 2 min 20 seconds we first find the circumference of the circular track. And we know that the circumference of the circular track is equal to the distance travelled in one round.

• So, we get the circumference of the track as 658.271. To find number of rounds that athlete made in 140 seconds (2 Min 20 seconds). We divided 104 by 4 and we get 35.

• Now, We know number of rounds that athlete made on circular track and that is 35. Now, Multiplying 35 by 658.271, we get the total distance travelled by athlete i.e. 2200 meters.

• And since the track is circular and athlete returns to the same position, therefore the displacement remains same i.e. 200 meters.

Answer 2

Answer:

At the end of 2 min 20 sec.,

• Distance covered is 2200m

• Displacement is 200m.

Explanation:

Given:

Diameter of circular track = 200m

Time taken for 1 round = 40 sec.

To find :

The distance covered and displacement

Solution :

Diameter = 200m

Radius =

200 / 2

100m

Therefore,

Radius = 100m

Time taken for 1 round = 40 sec.

First convert minute into seconds

So,

2min. 20 sec. = 140 seconds

Number of round = 140 / 40

3.5 means 3 and half round

Therefore,

Number of round = 3.5

Circumference of circle = 2 π r

Distance covered = 3.5 × Circumference of circular track

➙ 3.5 × 2 π r

➙ 3.5 × 2 × 22 / 7 × 100

➙ 2200m

Therefore,

At the end of 2 min 20 sec.,

Distance covered is 2200m

Displacement is 200m.