Question

$\overrightarrow{ A }$ is a vector quantity such that $|\overrightarrow{ A }|=$ non-zero constant. Which of the following expressions is true for $\overrightarrow{ A }$ ?

• A. $\overrightarrow{ A } \cdot \overrightarrow{ A }=0$
• B. $\overrightarrow{ A } \times \overrightarrow{ A }<0$
• C. $\overrightarrow{ A } \times \overrightarrow{ A }=0$
• D. $\overrightarrow{ A } \times \overrightarrow{ A }>0$

Answer 1

Answer: (C)

$|\overrightarrow{ A }| \neq 0$
$\overrightarrow{ A } \times \overrightarrow{ A }=|\overrightarrow{ A }||\overrightarrow{ A }| \sin 0^{\circ} \hat{ n }=0$