| Exam Board | Edexcel |
|---|---|
| Module | M3 (Mechanics 3) |
| Year | 2013 |
| Session | June |
| Marks | 6 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Circular Motion 1 |
| Type | Rotating disc with friction |
| Difficulty | Moderate -0.3 This is a straightforward application of circular motion with friction. Students need to convert angular speed to rad/s, apply F=mrω², set friction equal to centripetal force, and solve for μ. It's a standard M3 question requiring routine application of formulas with minimal problem-solving insight, making it slightly easier than average. |
| Spec | 3.03r Friction: concept and vector form3.03t Coefficient of friction: F <= mu*R model6.05b Circular motion: v=r*omega and a=v^2/r6.05c Horizontal circles: conical pendulum, banked tracks |
1.
\begin{figure}[h]
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\caption{Figure 1}
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A rough disc is rotating in a horizontal plane with constant angular speed 20 revolutions per minute about a fixed vertical axis through its centre $O$. A particle $P$ rests on the disc at a distance 0.4 m from $O$, as shown in Figure 1. The coefficient of friction between $P$ and the disc is $\mu$. The particle $P$ is on the point of slipping.
Find the value of $\mu$.\\
\hfill \mbox{\textit{Edexcel M3 2013 Q1 [6]}}