\textbf{161-} A bullet of mass $100\,\text{g}$ is fired from height $h$ under vacuum conditions and reaches the ground with some velocity. If the kinetic energy of the bullet at the moment it hits the ground is $24/2\,\text{J}$, the average speed of the bullet during the last second of its motion is how many meters per second?
$$\left(g = 10\,\frac{\text{m}}{\text{s}^2}\right)$$
\begin{itemize}
\item[(1)] 22
\item[(2)] 17
\item[(3)] 15
\item[(4)] 12
\end{itemize}