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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
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
If $\vec{A}+\vec{B}+\vec{C}=0$ then $\vec{A} \times \vec{B}$ is ............
If the angle between two vectors $A$ and $B$ is $120^{\circ}$, its resultant $C$ will be
The vector sum of two forces is perpendicular to their vector differences. In that case, the force