| Exam Board | OCR |
|---|---|
| Module | M2 (Mechanics 2) |
| Marks | 10 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Moments |
| Type | Rod with string perpendicular |
| Difficulty | Standard +0.3 This is a standard M2 statics problem involving a rod in equilibrium with straightforward application of resolving forces and taking moments. The geometry is given (right angle), eliminating the need to find angles. Part (i) requires a simple moment equation about A, while part (ii) involves resolving forces in two directions—both are routine techniques for this module with no conceptual challenges. |
| Spec | 3.03m Equilibrium: sum of resolved forces = 03.03n Equilibrium in 2D: particle under forces3.04b Equilibrium: zero resultant moment and force |
\includegraphics{figure_5}
A uniform rod $AB$ of length 60 cm and weight 15 N is freely suspended from its end $A$. The end $B$ of the rod is attached to a light inextensible string of length 80 cm whose other end is fixed to a point $C$ which is at the same horizontal level as $A$. The rod is in equilibrium with the string at right angles to the rod (see diagram).
\begin{enumerate}[label=(\roman*)]
\item Show that the tension in the string is 4.5 N. [4]
\item Find the magnitude and direction of the force acting on the rod at $A$. [6]
\end{enumerate}
\hfill \mbox{\textit{OCR M2 Q5 [10]}}