Question

an athlete completes half of the circle of radius 2m in 5 sec. Then the average velocity of the athlete is
Plz answer fast​

Answer 1

Circumference of a circle = 2πr

Circumference = 2×22/7*2

                        ⇒88/7 = 12.5m

Half of circle = 12.5/2 = 6.25m

Time taken is 5 sec

Avg Velocity = Distace/Time = 6.25/5 = 1.25m/s

Answer 2

Answer:

The diameter of the circular track is given as 200 m. That is, 2r=200 m.

From this radius is calculated as Radius, r = 100 m.

In 40 sec the athlete complete one round. So, in 2 mins and 20 secs, that is, 140 sec the athlete will complete = 140 / 40 = 3.5 (three and a half) rounds.

One round is considered as the circumference of the circular track.

The distance covered in 140 sec = 2πr×3.5=2×3.14×100×3.5=2200 m.

For each complete round the displacement is zero. Therefore for 3 complete rounds, the displacement will be zero.

At the end of his motion, the athlete will be in the diametrically opposite position. That is, displacement = diameter = 200 m.

Hence, the distance covered is 2200 m and the displacement is 200 m.