Answer
$-\mathbf{j}$
Work Step by Step
Therefore,
$\begin{align}
& \left\| \mathbf{v} \right\|=\sqrt{{{0}^{2}}+{{\left( -5 \right)}^{2}}} \\
& =5
\end{align}$
So,
$\begin{align}
& \frac{\mathbf{v}}{\parallel \mathbf{v}\parallel }=\frac{0}{5}\mathbf{i}-\frac{5}{5}\mathbf{j} \\
& =0\mathbf{i}-\mathbf{j} \\
& =-\mathbf{j}
\end{align}$
