Four persons $P, Q, R$ and $S$ are initially at the four corners of a square of side $d$. Each person now moves with a constant speed $v$ in such a way that $P$ always moves directly towards $Q, Q$ towards $R$. $R$ towards $S$, and $S$ towards $P$. The four persons will meet after time ........
$\frac{d}{2 v}$
$\frac{d}{v}$
$\frac{3 d}{2 v}$
They will never meet
A vector $\overrightarrow a $ is turned without a change in its length through a small angle $d\theta .$The value of $|\Delta \overrightarrow a |$ and $\Delta a$ are respectively
If $\vec{A}+\vec{B}+\vec{C}=0$ then $\vec{A} \times \vec{B}$ is ............
$A =2 \hat{ i }+\hat{ j }, B =3 \hat{ j }-\hat{ k }$ and $C =6 \hat{ i }-2 \hat{ k }$ Value of $A -2 B +3 C$ would be
The component of a vector along any other direction is
Consider a vector $F =4 \hat{ i }-3 \hat{ j }$. Another vector perpendicular of $F$ is