$4 \cdot 206$ There are two forces $f_{1} 、 f_{2}$ acting on the origin $O$ of the coordinate axes,
$$
\begin{array}{l}
\vec{f}_{1}=\overrightarrow{O A}=\sqrt{2}\left(\cos 45^{\circ}+i \sin 45^{\circ}\right), \\
\overrightarrow{f_{2}}=\overrightarrow{O B}=2\left[\cos \left(-30^{\circ}\right)+i \sin \left(-30^{\circ}\right)\right] .
\end{array}
$$
(1) Find the magnitude and direction of their resultant force;
(2) Find the distance between points $A$ and $B$ (accurate to 0.1).