A farmer moves along the boundary of a square field of side 10m in 40 secs. What will be the magnitude of displacement of the farmer at the end of 2 minutes 120 seconds from his initial position ?

 -Shresthi Goyal, Subject Matter Expert at Edumarz

Answer:  Converting 2 minutes 20 seconds into seconds

 1 min = 60 seconds 

2 mins = 120 seconds

 2mins 20 seconds = 140 seconds.

Since A = 10m (side of a square),

In 40 seconds, he travel 10m,

 In 80 seconds, he travel 20m,

 In 120 seconds, he travel 30m,

 In 140 seconds, he travel 35m

So, firstly he travelled from O to A, then A to B, then B to C and finally C to D. 

Since, displacement is the shortest distance between the initial and the final point.

So, displacement is measured from O to D, i.e. 5m