Two vectors of the same magnitude have a resultant equal to either of the two vectors. The angle between the two vectors is: (in $^{\circ}$)

Is it possible that $\vec{A} + \vec{B} = \vec{A} - \vec{B}$?

$A$ vector of length $\ell$ is turned by an angle $\theta$. Find the change in the position vector of the tip.

Two forces $3\,N$ and $2\,N$ are at an angle $\theta$ such that the resultant is $R$. The first force is now increased to $6\,N$ and the resultant becomes $2R$. The value of $\theta$ is ....... $^\circ$.

$A$ car travels $6 \, km$ at an angle of $45^o$ north of east and then travels a distance of $4 \, km$ at an angle of $135^o$ north of east. How far is the final point from the starting point? What angle does the straight line joining its initial and final position make with the east direction?

Among the given pairs of vectors,the resultant of two vectors can never be $3$ units. The vectors are