| Exam Board | Edexcel |
|---|---|
| Module | M2 (Mechanics 2) |
| Year | 2021 |
| Session | June |
| Marks | 9 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Moments |
| Type | Rod hinged to wall with string support |
| Difficulty | Standard +0.3 This is a standard M2 moments problem requiring equilibrium conditions (sum of moments = 0, resolving forces) with straightforward geometry. The setup is typical textbook fare with given angles and lengths, requiring calculation of tension via moments about A, then finding the reaction force by resolving. Slightly above average difficulty due to the two-part structure and need to handle both moment and force resolution, but uses entirely standard techniques with no novel insight required. |
| Spec | 3.04a Calculate moments: about a point3.04b Equilibrium: zero resultant moment and force |
5.
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\caption{Figure 3}
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A uniform rod, of length $8 a$ and mass $M$, has one end freely hinged to a fixed point $A$ on a vertical wall. One end of a light inextensible string is attached to the rod at the point $B$, where $A B = 5 a$. The other end of the string is attached to the wall at the point $C$, where $A C = 5 a$ and $C$ is vertically above $A$. The rod rests in equilibrium in a vertical plane perpendicular to the wall with angle $B A C = 70 ^ { \circ }$, as shown in Figure 3.
\begin{enumerate}[label=(\alph*)]
\item Find, in terms of $M$ and $g$, the tension in the string.
The magnitude of the force acting on the rod at $A$ is $\lambda M g$, where $\lambda$ is a constant.
\item Find, to 2 significant figures, the value of $\lambda$.
\end{enumerate}
\hfill \mbox{\textit{Edexcel M2 2021 Q5 [9]}}