Question

A vector ${\overrightarrow{F}}_1$ acts along positive X – axis. If its vector product with another vector ${\overrightarrow{F}}_2$ is zero, ${\overrightarrow{F}}_2$ could be

• A. 4j
• B. $-(\hat{i}+\hat{j})$
• C. (j+k)
• D. $-4\hat{i}$

Answer 1

The correct option is D $-4\hat{i}$

Let ${\overrightarrow{F}}_1=x\hat{i}$
As, ${\overrightarrow{F}}_1\times {\overrightarrow{F}}_2=0$
And only $\hat{i}\times \hat{i}=0$
$\therefore F_2=-4\hat{i}$