Question

$(\overrightarrow{P}+\overrightarrow{Q})$ is a unit vector along $X$-axis. lf $\overrightarrow{P}=\hat{i}+\hat{k}$ then what is $\overrightarrow{Q}$?

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

Answer 1

The correct option is B $-\hat{k}$

$\overrightarrow{P}+\overrightarrow{Q}$ is in $\hat{i}$ direction and $\overrightarrow{P}=\hat{i}+\hat{k}$
Therefore, $\overrightarrow{Q}=-\hat{k}$ because $\overrightarrow{P}+\overrightarrow{Q}$ is a unit vector.