| Exam Board | OCR |
|---|---|
| Module | M1 (Mechanics 1) |
| Year | 2009 |
| Session | June |
| Marks | 9 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Forces, equilibrium and resultants |
| Type | Connected particles on inclined plane |
| Difficulty | Standard +0.3 This is a standard connected particles problem requiring Newton's second law applied to two bodies with friction. Part (i) involves resolving forces on an inclined plane and using F=ma (routine M1 technique). Part (ii) requires finding friction coefficient from the other body's equation. While it has multiple steps, it follows a very standard M1 template with no novel insight required—slightly easier than average due to its predictable structure. |
| Spec | 3.03c Newton's second law: F=ma one dimension3.03f Weight: W=mg3.03k Connected particles: pulleys and equilibrium3.03r Friction: concept and vector form |
\includegraphics{figure_3}
The diagram shows a small block $B$, of mass $3$ kg, and a particle $P$, of mass $0.8$ kg, which are attached to the ends of a light inextensible string. The string is taut and passes over a small smooth pulley. $B$ is held at rest on a horizontal surface, and $P$ lies on a smooth plane inclined at $30°$ to the horizontal. When $B$ is released from rest it accelerates at $0.2$ m s$^{-2}$ towards the pulley.
\begin{enumerate}[label=(\roman*)]
\item By considering the motion of $P$, show that the tension in the string is $3.76$ N. [4]
\item Calculate the coefficient of friction between $B$ and the horizontal surface. [5]
\end{enumerate}
\hfill \mbox{\textit{OCR M1 2009 Q3 [9]}}