Question

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

Answer 1

Total distance covered 10 m in 40 s
Total time taken = 2 min 20 sec = 140 s
Total round completed = 140/40=3.5 rounds


So If an object moves from A to D, the shortest path will be from A to C. So displacement is AC, that we will find by pythagoras theorem.

$A{C}^2=A{B}^2+B{C}^2$
$A{C}^2=(10{)}^2+(10{)}^2$
$A{C}^2=100+100$
$A{C}^2=200$

$AC=\sqrt{200}$

$AC=10\sqrt{2}$