Edexcel M3 2021 January — Question 1

Exam BoardEdexcel
ModuleM3 (Mechanics 3)
Year2021
SessionJanuary
TopicCentre of Mass 2

1. \begin{figure}[h]
\includegraphics[alt={},max width=\textwidth]{8a687d17-ec7e-463f-84dd-605f5c230db1-02_469_758_251_593} \captionsetup{labelformat=empty} \caption{Figure 1}
\end{figure} The region \(R\), shown shaded in Figure 1, is bounded by the curve with equation \(y = \frac { 1 } { x }\), the line with equation \(x = 1\), the positive \(x\)-axis and the line with equation \(x = a\) where \(a > 1\) A uniform solid \(S\) is formed by rotating \(R\) through \(2 \pi\) radians about the \(x\)-axis.
  1. Show that the volume of \(S\) is $$\pi \left( 1 - \frac { 1 } { a } \right)$$
  2. Find the \(x\) coordinate of the centre of mass of \(S\).