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