\textbf{174.} A body of mass $m$ with a constant force of $5\,\dfrac{\text{N}}{\text{cm}}$ is connected to a spring of length 2cm. We pull and release the body on a frictionless horizontal surface. It starts oscillating. At the moment the oscillation speed reaches $\dfrac{\sqrt{2}}{2}$ of the maximum speed, how many joules is the mechanical energy of its translational motion?
\begin{itemize}
\item[(1)] 0.1
\item[(2)] 0.2
\item[(3)] 0.3
\item[(4)] 0.4
\end{itemize}