\begin{align}
	\v{p}_1' &= mv\v{n}_0+m_1(\v{p}_1+\v{p}_2)/(m_1+m_2), \\
	\v{p}_2' &= -mv\v{n}_0+m_2(\v{p}_1+\v{p}_2)/(m_1+m_2),
\end{align}
