Question

an athelete complete one round of a circular path in 40 s. Find the displacement at the end of 2miin 20 s

Answer 1

In 2 min ,
He can complete 3 rounds ,
then displacement after three round is '0'

In remaining 20 seconds,
He can complete hall round,
then the displace after 20 second is '2R'

therefore the total displacement after 2 min 20 sec is '2R'
here R is the radius of the circular path 

Answer 2

2 min 20s is equal to 140 s.

In 120 s, the athlete will complete 3 rounds.

In another 20 s, he will complete another half round.

So his displacement is equal to the diameter of the circular path.