Question

An athlete complete one round of circular park in 40s. The radius of circular park is 77m. He moves on it for 100s. Find distance and displacement covered by him.​

Answer 1

Answer:

1 round covered in 40 seconds

so in 100 seconds he will move 5/2 round i.e. 2.5 rounds  of track

so as the  radius is = 77

Distance = (2pi r = 1 round ) so 2.5 round = 2pi r * 5/2 = 5pi r

Displacement = 2r as at last he has only completed half round so he will be on the other side od diameter of circle so = 2r = 154m

Explanation:

Answer 2

Given:

The time taken for 1 round = 40 second

The total time = 100 s

The radius of the park, r = 77 m

To Find:

The distance and displacement covered by the athlete.

Calculation:

- No of rounds = 100 / 40 = 2.5

- The distance travelled in 1 round = 2πr

⇒ d = 2 × (22/7) × 77 = 484 m

- The total distance covered by athlete = 2.5 × 484 = 1210 m

- On covering 2.5 rounds, he will reach at the diametrically opposite position from the starting point.

- So, displacement = 2 r = 2 × 77 = 154 m

- So, the distance covered by him is 1210 m and his displacement is ​154 m.