| Exam Board | Edexcel |
|---|---|
| Module | M2 (Mechanics 2) |
| Year | 2010 |
| Session | June |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Centre of Mass 1 |
| Type | Frame with straight rod/wire components only |
| Difficulty | Standard +0.3 This is a standard M2 centre of mass question requiring systematic application of learned techniques: finding the centre of mass of a uniform wire frame using symmetry and the formula for composite bodies (part a), then applying equilibrium conditions for a suspended body (part b). While it involves multiple steps and careful coordinate work, it follows predictable patterns taught in M2 with no novel problem-solving required. |
| Spec | 6.04b Find centre of mass: using symmetry6.04c Composite bodies: centre of mass6.04e Rigid body equilibrium: coplanar forces |
\includegraphics{figure_1}
A triangular frame is formed by cutting a uniform rod into 3 pieces which are then joined to form a triangle $ABC$, where $AB = AC = 10$ cm and $BC = 12$ cm, as shown in Figure 1.
\begin{enumerate}[label=(\alph*)]
\item Find the distance of the centre of mass of the frame from $BC$.
(5)
\end{enumerate}
The frame has total mass $M$. A particle of mass $M$ is attached to the frame at the mid-point of $BC$. The frame is then freely suspended from $B$ and hangs in equilibrium.
\begin{enumerate}[label=(\alph*)]
\setcounter{enumi}{1}
\item Find the size of the angle between $BC$ and the vertical.
(4)
\end{enumerate}
\hfill \mbox{\textit{Edexcel M2 2010 Q3}}