Question

an athlete covers one round of the circular track in 200m in 30 sec.
find 1 ) the distance traveled by the athlete.

2) the magnitude of displacement of the athlete at the end of 30 sec

Answer 1

SOLUTION : The circumference of the track = pi*diameter(d)

= pi*200 m = 628.31m

Now, 2min 20 secs. = 120+20 = 140 secs

For 40 secs….distance covered = 628.31

Therefore for 140 secs…distance covered =

(628.31 * 140)/40 = 2199.085m..Thats your first answer.

Now , for displacement

140/40= 3.5 , so eventually the athlete will complete 3.5 rounds in 2min 20secs.

At the the end of third round athlete will again reach the starting point,so displacement will be zero at the end of third round. Therefore final displacement would be accounted for the remaining 0.5 round, so displacement being the shortest distance. it will be equal to diameter of the track, i.e. 200 m

Therefore final answers are

Distance covered = 2199.085m

Dispacement = 200m