When $n$ vectors of different magnitudes are added, we get a null vector. Then the value of $n$ cannot be
$11$
$4$
$3$
$2$
$\vec{A}$ is a vector of magnitude $2.7$ units due east. What is the magnitude and direction of vector $4 \vec{A}$ ?
Mark the correct statement :-
The vector that must be added to the vector $\hat i - 3\hat j + 2\hat k$ and $3\hat i + 6\hat j - 7\hat k$ so that the resultant vector is a unit vector along the $y-$axis is