4.
\begin{figure}[h]
\includegraphics[alt={},max width=\textwidth]{7ba14d10-1b57-4930-8d65-f21088c5d513-06_305_607_246_701}
\captionsetup{labelformat=empty}
\caption{Figure 1}
\end{figure}
A particle \(P\) of mass 6 kg lies on the surface of a smooth plane. The plane is inclined at an angle of \(30 ^ { \circ }\) to the horizontal. The particle is held in equilibrium by a force of magnitude 49 N , acting at an angle \(\theta\) to the plane, as shown in Figure 1. The force acts in a vertical plane through a line of greatest slope of the plane.
- Show that \(\cos \theta = \frac { 3 } { 5 }\).
- Find the normal reaction between \(P\) and the plane.
The direction of the force of magnitude 49 N is now changed. It is now applied horizontally to \(P\) so that \(P\) moves up the plane. The force again acts in a vertical plane through a line of greatest slope of the plane.
- Find the initial acceleration of \(P\).
\(\_\_\_\_\)}