Question

when athlete completes a round of a circular track of diameter 200m in 20 seconds calculate-(i) the distance travelled by athelete.(ii) the magnitude of the displacement of the athlete at the end of 1 minute 10 second​

Answer 1

Given that the athelete runs around a circular track of diameter 200 m or radius 100 m in time, t = 20 seconds.

(a) Distance travelled by athelete

After completing one round, the distance travelled by the athlete is equal to the circumference of the circular track,

⇒ Distance travelled = 2πr

⇒ Distance travelled =2×3.14 × 100

⇒ Distance travelled = 628 m

(b) Magnitude of displacement after 1 minute 10 seconds.

We know, after every 20 seconds, the athelete completes one round and the displacement he makes is zero. So, In 1 minute 10 seconds or (60+10) = 70 seconds the athelete would have covered 3 and a half round. Which means the displacement will be equal to the diameter of the circular track.

⇒ Displacement = 2 × Radius

⇒ Displacement = 200 m

Answer 2

Answer:

Given :-

Diameter = 200 m

Time = 20 second

To Find '-

The distance travelled by athelete.(ii) the magnitude of the displacement of the athlete at the end of 1 minute 10 second

Solution :-

For finding distance

Distance covered = Circumference of circle

Circumference = πd

Circumference = π × 200

Circumference = 200π

For magnitude

Magnitude = 2 × Radius

Radius = 200/2

Radius = 100 m

Magnitude = 2 × 100

Magnitude = 200 m