3.
\begin{figure}[h]
\includegraphics[alt={},max width=\textwidth]{7a65555e-1bb2-4947-8e70-50f267017bfd-06_472_208_343_1102}
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\caption{Figure 1}
\end{figure}
Two particles, \(P\) and \(Q\), have masses \(4 m\) and \(2 m\) respectively. The particles are connected by a light inextensible string. A second light inextensible string has one end attached to \(Q\). Both strings are taut and vertical, as shown in Figure 1.
The particles are accelerating vertically downwards.
Given that the tension in the string connecting the two particles is \(3 m g\), find, in terms of \(m\) and \(g\), the tension in the upper string.