| Exam Board | Edexcel |
|---|---|
| Module | M1 (Mechanics 1) |
| Year | 2012 |
| Session | January |
| Marks | 9 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Moments |
| Type | Beam on point of tilting |
| Difficulty | Standard +0.3 This is a standard M1 moments question requiring taking moments about a pivot point to find the center of mass position, then applying equilibrium conditions. The setup is straightforward with clear geometry, and part (a) is a 'show that' which guides students to the answer. Part (b) requires resolving forces and taking moments again, but follows a predictable pattern typical of textbook exercises. Slightly easier than average due to the guided nature and standard approach. |
| Spec | 3.04a Calculate moments: about a point3.04b Equilibrium: zero resultant moment and force |
4.
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\caption{Figure 1}
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A non-uniform $\operatorname { rod } A B$, of mass $m$ and length $5 d$, rests horizontally in equilibrium on two supports at $C$ and $D$, where $A C = D B = d$, as shown in Figure 1. The centre of mass of the rod is at the point $G$. A particle of mass $\frac { 5 } { 2 } m$ is placed on the rod at $B$ and the rod is on the point of tipping about $D$.
\begin{enumerate}[label=(\alph*)]
\item Show that $G D = \frac { 5 } { 2 } d$.
The particle is moved from $B$ to the mid-point of the rod and the rod remains in equilibrium.
\item Find the magnitude of the normal reaction between the support at $D$ and the rod.
\end{enumerate}
\hfill \mbox{\textit{Edexcel M1 2012 Q4 [9]}}