| Exam Board | WJEC |
|---|---|
| Module | Unit 2 (Unit 2) |
| Year | 2018 |
| Session | June |
| Marks | 7 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Pulley systems |
| Type | Particle on smooth horizontal surface, particle hanging |
| Difficulty | Moderate -0.8 This is a standard connected particles problem requiring Newton's second law applied to two objects. Part (a) involves routine setup of two equations (F=ma for each mass) and simultaneous solving—a textbook exercise with no novel insight needed. Part (b) is a simple conceptual statement. The 6-mark allocation reflects multiple steps but the method is entirely procedural and well-practiced at A-level. |
| Spec | 3.03c Newton's second law: F=ma one dimension3.03d Newton's second law: 2D vectors3.03k Connected particles: pulleys and equilibrium3.03o Advanced connected particles: and pulleys |
The diagram shows two objects $A$ and $B$, of mass 3 kg and 5 kg respectively, connected by a light inextensible string passing over a light smooth pulley fixed at the end of a smooth horizontal surface. Object $A$ lies on the horizontal surface and object $B$ hangs freely below the pulley.
\includegraphics{figure_8}
Initially, $B$ is supported so that the objects are at rest with the string just taut. Object $B$ is then released.
\begin{enumerate}[label=(\alph*)]
\item Find the magnitude of the acceleration of $A$ and the tension in the string. [6]
\item State briefly what effect a rough pulley would have on the tension in the string. [1]
\end{enumerate}
\hfill \mbox{\textit{WJEC Unit 2 2018 Q08 [7]}}