| Exam Board | SPS |
|---|---|
| Module | SPS FM Mechanics (SPS FM Mechanics) |
| Year | 2021 |
| Session | September |
| Marks | 8 |
| Topic | Pulley systems |
| Type | Particle on rough horizontal surface, particle hanging |
| Difficulty | Standard +0.3 This is a standard connected particles problem requiring application of SUVAT equations and Newton's second law. Part (a) is straightforward kinematics with given values, parts (b) and (c) involve routine force equations for the two-body system. The problem requires multiple steps but uses well-practiced techniques with no novel insight needed, making it slightly easier than average. |
| Spec | 3.02d Constant acceleration: SUVAT formulae3.03c Newton's second law: F=ma one dimension3.03k Connected particles: pulleys and equilibrium |
A box $A$ of mass 0.8 kg rests on a rough horizontal table and is attached to one end of a light inextensible string. The string passes over a smooth pulley fixed at the edge of the table. The other end of the string is attached to a sphere $B$ of mass 1.2 kg, which hangs freely below the pulley. The magnitude of the frictional force between $A$ and the table is $F$ N. The system is released from rest when the string is taut. After release, $B$ descends a distance of 0.9 m in 0.8 s. Modelling $A$ and $B$ as particles, calculate
\begin{enumerate}[label=(\alph*)]
\item the acceleration of $B$, [2]
\item the tension in the string, [3]
\item the value of $F$. [3]
\end{enumerate}
\hfill \mbox{\textit{SPS SPS FM Mechanics 2021 Q4 [8]}}