7.
\begin{figure}[h]
\includegraphics[alt={},max width=\textwidth]{5c908e75-73df-46be-93bb-09dba2cb3b7e-12_150_1104_255_422}
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\caption{Figure 3}
\end{figure}
Two particles \(P\) and \(Q\), of mass 0.3 kg and 0.5 kg respectively, are joined by a light horizontal rod. The system of the particles and the rod is at rest on a horizontal plane. At time \(t = 0\), a constant force \(\mathbf { F }\) of magnitude 4 N is applied to \(Q\) in the direction \(P Q\), as shown in Figure 3. The system moves under the action of this force until \(t = 6 \mathrm {~s}\). During the motion, the resistance to the motion of \(P\) has constant magnitude 1 N and the resistance to the motion of \(Q\) has constant magnitude 2 N .
Find
- the acceleration of the particles as the system moves under the action of \(\mathbf { F }\),
- the speed of the particles at \(t = 6 \mathrm {~s}\),
- the tension in the rod as the system moves under the action of \(\mathbf { F }\).
At \(t = 6 \mathrm {~s} , \mathbf { F }\) is removed and the system decelerates to rest. The resistances to motion are unchanged. Find
- the distance moved by \(P\) as the system decelerates,
- the thrust in the rod as the system decelerates.