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If the angle between two vectors $A$ and $B$ is $120^{\circ}$, its resultant $C$ will be
A force of $5 N$ acts on a particle along a direction making an angle of $60^{\circ}$ with vertical. Its vertical component will be $.........\,N$
A river is flowing from east to west at a speed of $5\ m/min$ . A man on south bank of river, capable of swimming $10\ m/min$ in still water, wants to swim across the river in shortest time. He should swim
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 ........
If $\vec{A}+\vec{B}+\vec{C}=0$ then $\vec{A} \times \vec{B}$ is ............