| Exam Board | OCR MEI |
|---|---|
| Module | AS Paper 1 (AS Paper 1) |
| Session | Specimen |
| Marks | 3 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Newton's laws and connected particles |
| Type | Block on rough horizontal surface – equilibrium (finding friction, normal reaction, or coefficient of friction) |
| Difficulty | Easy -1.8 This is a very basic equilibrium question requiring only recognition that forces must balance (no calculation needed) and recall of normal reaction and friction forces. It tests fundamental understanding rather than problem-solving skills, making it significantly easier than typical A-level mechanics questions. |
| Spec | 3.03b Newton's first law: equilibrium3.03i Normal reaction force3.03r Friction: concept and vector form |
| Answer | Marks | Guidance |
|---|---|---|
| E.g. The particle is in equilibrium [and the given forces cannot sum to zero as at 90°] | B1 | AO 2.2a |
| Answer | Marks | Guidance |
|---|---|---|
| Friction 10 N [to give horizontal resultant of 0] | B1 | AO 3.3 |
| Normal reaction from table. 8 N [to give vertical resultant of 0] | B1 | AO 1.2 |
| *Alternative method:* One extra force that gives equilibrium. Components 10 N \(\rightarrow\) and 8 N \(\uparrow\) | B1 | AO 3.3 |
| Components from Friction \(\rightarrow\) and normal reaction \(\uparrow\) | B1 | AO 1.2 |
**Question 3(a):**
E.g. The particle is in equilibrium [and the given forces cannot sum to zero as at 90°] | **B1** | AO 2.2a | oe; Accept "without another force present, the particle would be moving on a rough surface without a frictional force" | [1 mark total]
---
**Question 3(b):**
Friction 10 N [to give horizontal resultant of 0] | **B1** | AO 3.3 | oe Accept 'Because the surface is rough' for 'Friction'
Normal reaction from table. 8 N [to give vertical resultant of 0] | **B1** | AO 1.2 | Oe
*Alternative method:* One extra force that gives equilibrium. Components 10 N $\rightarrow$ and 8 N $\uparrow$ | **B1** | AO 3.3 | oe Accept $\sqrt{164}$ at $\approx 39°$ to horizontal
Components from Friction $\rightarrow$ and normal reaction $\uparrow$ | **B1** | AO 1.2 | oe Accept 'because the surface is rough' for 'Friction' | [2 marks total]
---3 Fig. 3 shows a particle of weight 8 N on a rough horizontal table.\\
The particle is being pulled by a horizontal force of 10 N .\\
It remains at rest in equilibrium.
\begin{figure}[h]
\begin{center}
\includegraphics[alt={},max width=\textwidth]{970d2349-7705-4b66-9931-83613e5d852f-3_204_454_1311_255}
\captionsetup{labelformat=empty}
\caption{Fig. 3}
\end{center}
\end{figure}
\begin{enumerate}[label=(\alph*)]
\item What information given in the question, tells you that the forces shown in Fig. 3 cannot be the only forces acting on the particle?
\item The only other forces acting on the particle are due to the particle being on the table. State the types of these forces and their magnitudes.
\end{enumerate}
\hfill \mbox{\textit{OCR MEI AS Paper 1 Q3 [3]}}