Edexcel M1 2006 June — Question 4 11 marks

Exam BoardEdexcel
ModuleM1 (Mechanics 1)
Year2006
SessionJune
Marks11
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicMotion on a slope
TypeMotion with applied force on slope
DifficultyStandard +0.3 This is a standard M1 mechanics problem involving forces on a slope with friction. It requires resolving forces perpendicular and parallel to the plane, applying F=μR and Newton's second law. The 3-4-5 triangle simplifies calculations. While it has multiple steps, it follows a routine procedure with no novel insight required, making it slightly easier than average.
Spec3.03t Coefficient of friction: F <= mu*R model3.03v Motion on rough surface: including inclined planes

4. \begin{figure}[h]
\captionsetup{labelformat=empty} \caption{Figure 2} \includegraphics[alt={},max width=\textwidth]{3a8395fd-6e44-48a1-8c97-3365a284956a-05_273_611_319_676}
\end{figure} A particle \(P\) of mass 0.5 kg is on a rough plane inclined at an angle \(\alpha\) to the horizontal, where tan \(\alpha = \frac { 3 } { 4 }\). The particle is held at rest on the plane by the action of a force of magnitude 4 N acting up the plane in a direction parallel to a line of greatest slope of the plane, as shown in Figure 2. The particle is on the point of slipping up the plane.
  1. Find the coefficient of friction between \(P\) and the plane. The force of magnitude 4 N is removed.
  2. Find the acceleration of \(P\) down the plane.

AnswerMarks Guidance
(a) \(R = 0.5g \cos \alpha = 0.4g\)M1 A1
\(4 = F + 0.5g \sin \alpha\)M1 A1
\(F = \mu R\) usedM1
\(4 = 0.4g\mu + 0.3g \Rightarrow \mu \approx 0.27(0)\)M1 A1 (7)
(b) \(0.5a = 0.3g - 0.27 \times 0.4g \Rightarrow a \approx (+) 3.76 \text{ m s}^{-2}\) (or 3.8)M1 A2,1,0∇ A1 (4)
Guidance:
- (a) 1st two M1's require correct number of the correct terms, with valid attempt to resolve the correct relevant term (valid 'resolve' = x sin/cos).
- 4th M1 (dept) for forming equn in \(\mu\) + numbers only.
- (b) In first equn, allow their \(R\) or \(F\) in the equation for full marks. A marks: f.t. on their \(R\), \(F\) etc. Deduct one A mark (up to 2) for each wrong term. (Note slight change from original scheme)
| (a) $R = 0.5g \cos \alpha = 0.4g$ | M1 A1 | |
| $4 = F + 0.5g \sin \alpha$ | M1 A1 | |
| $F = \mu R$ used | M1 | |
| $4 = 0.4g\mu + 0.3g \Rightarrow \mu \approx 0.27(0)$ | M1 A1 | (7) |
| (b) $0.5a = 0.3g - 0.27 \times 0.4g \Rightarrow a \approx (+) 3.76 \text{ m s}^{-2}$ (or 3.8) | M1 A2,1,0∇ | A1 (4) |

**Guidance:** 
- (a) 1st two M1's require correct number of the correct terms, with valid attempt to resolve the correct relevant term (valid 'resolve' = x sin/cos).
- 4th M1 (dept) for forming equn in $\mu$ + numbers only.
- (b) In first equn, allow their $R$ or $F$ in the equation for full marks. A marks: f.t. on their $R$, $F$ etc. Deduct one A mark (up to 2) for each wrong term. (Note slight change from original scheme)

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4.

\begin{figure}[h]
\begin{center}
\captionsetup{labelformat=empty}
\caption{Figure 2}
  \includegraphics[alt={},max width=\textwidth]{3a8395fd-6e44-48a1-8c97-3365a284956a-05_273_611_319_676}
\end{center}
\end{figure}

A particle $P$ of mass 0.5 kg is on a rough plane inclined at an angle $\alpha$ to the horizontal, where tan $\alpha = \frac { 3 } { 4 }$. The particle is held at rest on the plane by the action of a force of magnitude 4 N acting up the plane in a direction parallel to a line of greatest slope of the plane, as shown in Figure 2. The particle is on the point of slipping up the plane.
\begin{enumerate}[label=(\alph*)]
\item Find the coefficient of friction between $P$ and the plane.

The force of magnitude 4 N is removed.
\item Find the acceleration of $P$ down the plane.
\end{enumerate}

\hfill \mbox{\textit{Edexcel M1 2006 Q4 [11]}}