If the magnitude of sum of two vectors is equal to the magnitude of difference of the two vectors, the angle between these vectors is ........ $^o$
$90$
$120$
$45$
$60$
If a particle moves from point $P (2,3,5)$ to point $Q (3,4,5)$. Its displacement vector be
If $\vec{P}+\vec{Q}=\overrightarrow{0}$, then which of the following is necessarily true?
Find the resultant of three vectors $\overrightarrow {OA} ,\,\overrightarrow {OB} $ and $\overrightarrow {OC} $ shown in the following figure. Radius of the circle is $R$.
The resultant of two vectors at an angle $150^{\circ}$ is $10$ units and is perpendicular to one vector. The magnitude of the smaller vector is ....... units