Question

 A farmer moves along the boundary of a square field of side 10m in 40 s. What will be the magnitude of displacement of the farmer at the end of 2 minutes 20 seconds from his initial position?​

Answer 1

Answer: Farmer takes 40 s to move along the boundary. Thus, after 3.5 round farmer will at point C of the field. Thus, after 2 min 20 seconds the displacement of farmer will be equal to 14.14 m north east from initial position.

Explanation:  Given side of square =10m, thus perimeter P=40m

Time taken to cover the boundary of 40 m =40 s

Thus in 1 second, the farmer covers a distance of 1 m

Now distance covered by the farmer in 2 min 20 seconds = 1×140=140m

Now the total number of rotation the farmer makes to cover a distance of 140 meters =  

perimeter

totaldistance

​ =3.5  

At this point, the farmer is at a point say B from the origin O

Thus the displacement s=  

10  

2

+10  

2

 from Pythagoras theorem.

s=10  

2

​  =14.14m