Question

A fly flies from a point $P(0,2,5)$ to the point $Q(3,1,6)$. The magnitude of displacement covered by it is

• A. $\sqrt{11}$
• B. $\sqrt{7}$
• C. $\sqrt{13}$
• D. $\sqrt{10}$

Answer 1

The correct option is A $\sqrt{11}$

Given, the two points where fly flies, so representing them vectorially we have
$\overrightarrow{P}=2\hat{j}+5\hat{k}$, and $\overrightarrow{Q}=3\hat{i}+\hat{j}+6\hat{k}$
Thus, the displacement covered by it is
$\overrightarrow{QP}=\overrightarrow{Q}-\overrightarrow{P}$
$\Rightarrow (3-0)\hat{i}+(1-2)\hat{j}+(6-5)\hat{k}=3\hat{i}-\hat{j}+\hat{k}$
$\Rightarrow |\overrightarrow{QP}|=\sqrt{3^2+(-1{)}^2+1^2}=\sqrt{11}$