| Exam Board | OCR |
|---|---|
| Module | M1 (Mechanics 1) |
| Marks | 11 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Friction |
| Type | Two-part friction scenarios |
| Difficulty | Standard +0.3 This is a standard M1 friction problem requiring application of F=μR and resolution of forces. Part (i) is straightforward (finding mass from limiting friction). Part (ii) involves resolving forces at an angle and solving simultaneous equations, which is routine for M1 students who have practiced these techniques. The problem requires multiple steps but follows predictable patterns with no novel insight needed, making it slightly easier than average. |
| Spec | 3.03e Resolve forces: two dimensions3.03m Equilibrium: sum of resolved forces = 03.03r Friction: concept and vector form3.03t Coefficient of friction: F <= mu*R model3.03u Static equilibrium: on rough surfaces |
A block of mass $m$ kg is at rest on a horizontal plane. The coefficient of friction between the block and the plane is $0.2$.
\begin{enumerate}[label=(\roman*)]
\item When a horizontal force of magnitude $5$ N acts on the block, the block is on the point of slipping. Find the value of $m$. [3]
\end{enumerate}
\begin{enumerate}[label=(\roman*)]
\setcounter{enumi}{1}
\item \includegraphics{figure_5ii}
When a force of magnitude $P$ N acts downwards on the block at an angle $\alpha$ to the horizontal, as shown in the diagram, the frictional force on the block has magnitude $6$ N and the block is again on the point of slipping. Find
\begin{enumerate}[label=(\alph*)]
\item the value of $\alpha$ in degrees,
\item the value of $P$.
\end{enumerate}
[8]
\end{enumerate}
\hfill \mbox{\textit{OCR M1 Q5 [11]}}