Edexcel M3 2021 January — Question 5

Exam BoardEdexcel
ModuleM3 (Mechanics 3)
Year2021
SessionJanuary
TopicSimple Harmonic Motion

5. \begin{figure}[h]
\includegraphics[alt={},max width=\textwidth]{8a687d17-ec7e-463f-84dd-605f5c230db1-16_720_232_251_858} \captionsetup{labelformat=empty} \caption{Figure 6}
\end{figure} The fixed points, \(A\) and \(B\), are a distance \(10 a\) apart, with \(B\) vertically above \(A\). One end of a light elastic string, of natural length \(2 a\) and modulus of elasticity \(2 m g\), is attached to a particle \(P\) of mass \(m\) and the other end is attached to \(A\). One end of another light elastic string, of natural length \(4 a\) and modulus of elasticity \(6 m g\), is attached to \(P\) and the other end is attached to \(B\). The particle \(P\) rests in equilibrium at the point \(C\), as shown in Figure 6.
  1. Show that each string has an extension of \(2 a\).
    (5) The particle \(P\) is now pulled down vertically, so that it is a distance \(a\) below \(C\) and then released from rest.
  2. Show that in the subsequent motion, \(P\) performs simple harmonic motion.
  3. Find, in terms of \(a\) and \(g\), the speed of \(P\) when it is a distance \(\frac { 7 } { 2 } a\) above \(A\).