| Exam Board | Edexcel |
|---|---|
| Module | Paper 3 (Paper 3) |
| Year | 2024 |
| Session | June |
| Marks | 3 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Friction |
| Type | Horizontal force only - find mass or coefficient |
| Difficulty | Easy -1.3 This is a straightforward two-part mechanics question requiring only basic recall and application of standard formulas: R = mg for the normal reaction, and F = μR for limiting friction. Both parts involve single-step calculations with no problem-solving or conceptual challenges, making it significantly easier than average A-level questions. |
| Spec | 3.03b Newton's first law: equilibrium3.03r Friction: concept and vector form3.03t Coefficient of friction: F <= mu*R model |
| Answer | Marks | Guidance |
|---|---|---|
| Answer | Mark | Guidance |
| \(0.5g\), \(\frac{1}{2}g\) or \(4.9\) (N) seen | B1 | cao, must be positive. B0 for \(\frac{49}{10}\). B0 if \(0.5g\) seen then \(g=9.81\) used (not isw). Answer must appear in (a) to earn mark; if no labelling, give BOD. |
| Answer | Marks | Guidance |
|---|---|---|
| Answer | Mark | Guidance |
| \(\frac{2}{7} \times 4.9\) oe seen | M1 | \(\frac{2}{7} \times\) their (a), must be a numerical value. If no answer for (a) or (a) incorrect and not used, allow correct restart e.g. \(\frac{2}{7}\times 4.9\) or \(\frac{2}{7}\times 0.5g\) or \(\frac{2}{7}\times 0.5\) (missing \(g\) is not an M error) |
| \(1.4\), \(1.40\) or \(\frac{1}{7}g\) | A1 | A0 for a fraction. \(X=\) not needed BUT A0 for \(F\) (or \(P\) or horizontal force) = correct answer if they don't state \(X=\)... If correct answer for \(F\) found and \(F=X\) stated, can score A1. N.B. \(1.4\), \(1.40\) or \(\frac{1}{7}g\) with no working scores M1A1 |
## Question 1:
### Part (a):
| Answer | Mark | Guidance |
|--------|------|----------|
| $0.5g$, $\frac{1}{2}g$ or $4.9$ (N) seen | B1 | cao, must be positive. B0 for $\frac{49}{10}$. B0 if $0.5g$ seen then $g=9.81$ used (not isw). Answer must appear in (a) to earn mark; if no labelling, give BOD. |
### Part (b):
| Answer | Mark | Guidance |
|--------|------|----------|
| $\frac{2}{7} \times 4.9$ oe seen | M1 | $\frac{2}{7} \times$ their (a), must be a numerical value. If no answer for (a) or (a) incorrect and not used, allow correct restart e.g. $\frac{2}{7}\times 4.9$ or $\frac{2}{7}\times 0.5g$ or $\frac{2}{7}\times 0.5$ (missing $g$ is not an M error) |
| $1.4$, $1.40$ or $\frac{1}{7}g$ | A1 | A0 for a fraction. $X=$ not needed **BUT** A0 for $F$ (or $P$ or horizontal force) = correct answer if they don't state $X=$... If correct answer for $F$ found and $F=X$ stated, can score A1. **N.B.** $1.4$, $1.40$ or $\frac{1}{7}g$ **with no working** scores M1A1 |
**Additional Notes:**
- Ignore units throughout question
- Use of $g=9.81$ penalised **once** for whole question (also applies to fractional answers $\frac{49}{10}$ and $\frac{7}{5}$)
- Penalise $g=9.81$ the first time it appears
- If $g=9.81$ used in (a): B0; if then used again in (b) giving $1.4$ or $1.40$, can score M1A1 in (b)
- If $g=9.81$ only used in (b): max M1A01.
\begin{figure}[h]
\begin{center}
\includegraphics[alt={},max width=\textwidth]{184043b7-1222-44fb-bc9f-3f484f72147b-02_108_997_242_534}
\captionsetup{labelformat=empty}
\caption{Figure 1}
\end{center}
\end{figure}
Figure 1 shows a particle $P$ of mass 0.5 kg at rest on a rough horizontal plane.
\begin{enumerate}[label=(\alph*)]
\item Find the magnitude of the normal reaction of the plane on $P$.
The coefficient of friction between $P$ and the plane is $\frac { 2 } { 7 }$\\
A horizontal force of magnitude $X$ newtons is applied to $P$.\\
Given that $P$ is now in limiting equilibrium,
\item find the value of $X$.
\end{enumerate}
\hfill \mbox{\textit{Edexcel Paper 3 2024 Q1 [3]}}