Edexcel M1 2008 June — Question 7 11 marks

Exam BoardEdexcel
ModuleM1 (Mechanics 1)
Year2008
SessionJune
Marks11
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicMotion on a slope
TypeString at angle to slope
DifficultyStandard +0.3 This is a standard M1 equilibrium problem on an inclined plane with a force at an angle. It requires resolving forces in two directions (parallel and perpendicular to the plane), applying F=μR for limiting friction, and solving simultaneous equations. While it involves multiple steps and careful angle work, it follows a well-practiced procedure with no novel insight required, making it slightly easier than the average A-level question.
Spec3.03e Resolve forces: two dimensions3.03m Equilibrium: sum of resolved forces = 03.03t Coefficient of friction: F <= mu*R model3.03u Static equilibrium: on rough surfaces

7. \begin{figure}[h]
\includegraphics[alt={},max width=\textwidth]{9dbbbc01-fb66-460d-a42e-2c37ec8b451a-10_291_726_265_607} \captionsetup{labelformat=empty} \caption{Figure 3}
\end{figure} A package of mass 4 kg lies on a rough plane inclined at \(30 ^ { \circ }\) to the horizontal. The package is held in equilibrium by a force of magnitude 45 N acting at an angle of \(50 ^ { \circ }\) to the plane, as shown in Figure 3. The force is acting in a vertical plane through a line of greatest slope of the plane. The package is in equilibrium on the point of moving up the plane. The package is modelled as a particle. Find
  1. the magnitude of the normal reaction of the plane on the package,
  2. the coefficient of friction between the plane and the package.

AnswerMarks Guidance
(a) \(R = 45\cos 40° + 4g\cos 30°\) giving \(R \approx 68\)M1 A2 (1, 0) DM1 A1 (5) Accept 68.4
(b) Use of \(F = \mu R\) with \(F + 4g\sin 30° = 45\cos 50°\) leading to \(\mu \approx 0.14\)M1 M1 A2 (1, 0) DM1 A1 (6) [11] Accept 0.136
**(a)** $R = 45\cos 40° + 4g\cos 30°$ giving $R \approx 68$ | M1 A2 (1, 0) DM1 A1 | (5) Accept 68.4

**(b)** Use of $F = \mu R$ with $F + 4g\sin 30° = 45\cos 50°$ leading to $\mu \approx 0.14$ | M1 M1 A2 (1, 0) DM1 A1 | (6) [11] Accept 0.136

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7.

\begin{figure}[h]
\begin{center}
  \includegraphics[alt={},max width=\textwidth]{9dbbbc01-fb66-460d-a42e-2c37ec8b451a-10_291_726_265_607}
\captionsetup{labelformat=empty}
\caption{Figure 3}
\end{center}
\end{figure}

A package of mass 4 kg lies on a rough plane inclined at $30 ^ { \circ }$ to the horizontal. The package is held in equilibrium by a force of magnitude 45 N acting at an angle of $50 ^ { \circ }$ to the plane, as shown in Figure 3. The force is acting in a vertical plane through a line of greatest slope of the plane. The package is in equilibrium on the point of moving up the plane. The package is modelled as a particle. Find
\begin{enumerate}[label=(\alph*)]
\item the magnitude of the normal reaction of the plane on the package,
\item the coefficient of friction between the plane and the package.
\end{enumerate}

\hfill \mbox{\textit{Edexcel M1 2008 Q7 [11]}}