161- According to the figure below, force $\mathbf{F}$ is applied to mass $m_1$ and the system begins to move with constant acceleration. The coefficient of lateral (kinetic) friction between each of the two masses and the horizontal surface is $\mu_k$. In the same situation, if force $\mathbf{F}$ is applied, the coefficient of lateral friction for each of the two masses with the horizontal surface is halved. How many times will the force applied to both masses together become? [Figure: Force F applied horizontally to mass $m_1$ which is in contact with mass $m_2$, both on a rough surface]
[(1)] $1$ (2) $2$
[(3)] $\dfrac{1}{2}$ (4) $\dfrac{1}{4}$
\textbf{161-} According to the figure below, force $\mathbf{F}$ is applied to mass $m_1$ and the system begins to move with constant acceleration. The coefficient of lateral (kinetic) friction between each of the two masses and the horizontal surface is $\mu_k$. In the same situation, if force $\mathbf{F}$ is applied, the coefficient of lateral friction for each of the two masses with the horizontal surface is halved. How many times will the force applied to both masses together become?
\textit{[Figure: Force F applied horizontally to mass $m_1$ which is in contact with mass $m_2$, both on a rough surface]}
\begin{itemize}
\item[(1)] $1$ \hfill (2) $2$
\item[(3)] $\dfrac{1}{2}$ \hfill (4) $\dfrac{1}{4}$
\end{itemize}