Let $\vec A\, = \,(\hat i\, + \,\hat j)\,$ and $\vec B\, = \,(2\hat i\, - \,\hat j)\,.$ The magnitude of a coplanar vector $\vec C$ such that $\vec A\cdot \vec C\, = \,\vec B\cdot \vec C\, = \vec A\cdot \vec B$ is given by
$\sqrt {\frac{5}{9}} $
$\sqrt {\frac{10}{9}} $
$\sqrt {\frac{20}{9}} $
$\sqrt {\frac{9}{12}} $
If a vector $\vec A$ is parallel to another vector $\vec B$ then the resultant of the vector $\vec A \times \vec B$ will be equal to
Show that the area of the triangle contained between the vectors $a$ and $b$ is one half of the magnitude of $a \times b .$
If $\left| {\vec A } \right|\, = \,2$ and $\left| {\vec B } \right|\, = \,4$ then match the relation in Column $-I$ with the angle $\theta $ between $\vec A$ and $\vec B$ in Column $-II$.
Column $-I$ | Column $-II$ |
$(a)$ $\vec A \,.\,\,\vec B \, = \,\,0$ | $(i)$ $\theta = \,{0^o}$ |
$(b)$ $\vec A \,.\,\,\vec B \, = \,\,+8$ | $(ii)$ $\theta = \,{90^o}$ |
$(c)$ $\vec A \,.\,\,\vec B \, = \,\,4$ | $(iii)$ $\theta = \,{180^o}$ |
$(d)$ $\vec A \,.\,\,\vec B \, = \,\,-8$ | $(iv)$ $\theta = \,{60^o}$ |