Given that $\vec A\, + \,\vec B\, = \,\vec C\,.$ If $\left| {\vec A} \right|\, = \,4,\,\,\left| {\vec B} \right|\, = \,5\,\,$ and $\left| {\vec C} \right|\, =\,\sqrt {61}$ the angle between $\vec A\,\,$ and $\vec B$ is ....... $^o$
$30$
$60$
$90$
$120$
If $\vec{P}+\vec{Q}=\overrightarrow{0}$, then which of the following is necessarily true?
The two vectors $\vec A = -2\widehat i + \widehat j + 3\widehat k$ and $\vec B = 7\widehat i + 5\widehat j + 3\widehat k$ are :-
Two vectors $P = 2\hat i + b\hat j + 2\hat k$ and $Q = \hat i + \hat j + \hat k$ will be parallel if $b=$ ........
The resultant of $\overrightarrow P $ and $\overrightarrow Q $ is perpendicular to $\overrightarrow P $. What is the angle between $\overrightarrow P $ and $\overrightarrow Q $
$ABC$ is an equilateral triangle. Length of each side is $a$ and centroid is point $O$. then $\overrightarrow{O A}+\overrightarrow{O B}+\overrightarrow{O C}=.......$