17 A uniform plank \(P Q\), of length 7 metres, lies horizontally at rest, in equilibrium, on two fixed supports at points \(X\) and \(Y\)
The distance \(P X\) is 1.4 metres and the distance \(Q Y\) is 2 metres as shown in the diagram below.
\includegraphics[max width=\textwidth, alt={}, center]{de8a7d38-a665-4feb-854e-ac83f413d133-26_56_689_534_762}
\includegraphics[max width=\textwidth, alt={}, center]{de8a7d38-a665-4feb-854e-ac83f413d133-26_225_830_607_694}
17
- The reaction force on the plank at \(X\) is \(4 g\) newtons.
17 - Show that the mass of the plank is 9.6 kilograms.
17
- (ii) Find the reaction force, in terms of \(g\), on the plank at \(Y\)
17 - The support at \(Y\) is moved so that the distance \(Q Y = 1.4\) metres.
The plank remains horizontally at rest in equilibrium.
It is claimed that the reaction force at \(Y\) remains unchanged.
Explain, with a reason, whether this claim is correct.