Question

$\overrightarrow{P}+\overrightarrow{Q}$ is a unit vector along $x-$axis. If $\overrightarrow{P}=\hat{i}-\hat{j}+\hat{k}$ , then what is $\overrightarrow{Q}$ ?

• A. $\hat{i}+\hat{j}-\hat{k}$
• B. $\hat{j}+\hat{k}$
• C. $\hat{i}+\hat{j}+\hat{k}$
• D. $\hat{j}-\hat{k}$

Answer 1

The correct option is D $\hat{j}-\hat{k}$

Given,
$\overrightarrow{P}=\hat{i}-\hat{j}+\hat{k}$
And
$\overrightarrow{P}+\overrightarrow{Q}$ is unit vector along $x-$axis,
$\overrightarrow{P}+\overrightarrow{Q}=\hat{i}$
$\hat{i}-\hat{j}+\hat{k}+\overrightarrow{Q}=\hat{i}$
$\overrightarrow{Q}=\hat{j}-\hat{k}$
Final answer: (b)