| Exam Board | OCR |
|---|---|
| Module | M1 (Mechanics 1) |
| Marks | 7 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Forces, equilibrium and resultants |
| Type | Multiple particles with intermediate connections |
| Difficulty | Standard +0.3 This is a standard two-particle connected system problem requiring straightforward application of Newton's second law to each particle separately, then solving simultaneous equations. While it involves multiple forces (weight, tension, air resistance), the setup is conventional and the solution method is routine for M1 students who have practiced connected particles problems. |
| Spec | 3.03c Newton's second law: F=ma one dimension3.03d Newton's second law: 2D vectors |
\includegraphics{figure_2}
Particles $A$ and $B$, of masses $0.2$ kg and $0.3$ kg respectively, are attached to the ends of a light inextensible string. Particle $A$ is held at rest at a fixed point and $B$ hangs vertically below $A$. Particle $A$ is now released. As the particles fall the air resistance acting on $A$ is $0.4$ N and the air resistance acting on $B$ is $0.25$ N (see diagram). The downward acceleration of each of the particles is $a$ m s$^{-2}$ and the tension in the string is $T$ N.
\begin{enumerate}[label=(\roman*)]
\item Write down two equations in $a$ and $T$ obtained by applying Newton's second law to $A$ and to $B$. [4]
\item Find the values of $a$ and $T$. [3]
\end{enumerate}
\hfill \mbox{\textit{OCR M1 Q2 [7]}}