Five equal forces of $10 \,N$ each are applied at one point and all are lying in one plane. If the angles between them are equal, the resultant force will be ........... $\mathrm{N}$
$0$
$10 $
$20$
$10\sqrt 2 $
If a particle moves from point $P (2,3,5)$ to point $Q (3,4,5)$. Its displacement vector be
Give the names of two methods for vector addition. Write the law of parallogram for vector addition.
The vectors $\vec{A}$ and $\vec{B}$ are such that
$|\vec{A}+\vec{B}|=|\vec{A}-\vec{B}|$
The angle between the two vectors is
The position vectors of points $A, B, C$ and $D$ are $\vec A = 3\hat i + 4\hat j + 5\hat k,\,\vec B = 4\hat i + 5\hat j + 6\hat k,\,\vec C = 7\hat i + 9\hat j + 3\hat k$ and $\vec D = 4\hat i + 6\hat j$ then the displacement vectors $\overrightarrow {AB} $ and $\overrightarrow {CD} $ are