| Exam Board | OCR |
|---|---|
| Module | M1 (Mechanics 1) |
| Year | 2009 |
| Session | January |
| Marks | 8 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Motion on a slope |
| Type | Modelling assumptions and refinements |
| Difficulty | Moderate -0.3 This is a straightforward two-part mechanics question requiring resolution of forces and application of Newton's second law or equilibrium conditions. Part (i) involves basic force resolution and F=ma with no friction, while part (ii) requires understanding of limiting equilibrium and friction (F=μR). Both are standard M1 techniques with no conceptual surprises, making it slightly easier than average for A-level. |
| Spec | 3.03c Newton's second law: F=ma one dimension3.03e Resolve forces: two dimensions3.03i Normal reaction force3.03r Friction: concept and vector form3.03t Coefficient of friction: F <= mu*R model3.03u Static equilibrium: on rough surfaces |
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\includegraphics[max width=\textwidth, alt={}, center]{470e70de-66ba-4dcc-a205-0c92f29471b1-3_200_897_269_625}
A block of mass 3 kg is placed on a horizontal surface. A force of magnitude 20 N acts downwards on the block at an angle of $30 ^ { \circ }$ to the horizontal (see diagram).\\
(i) Given that the surface is smooth, calculate the acceleration of the block.\\
(ii) Given instead that the block is in limiting equilibrium, calculate the coefficient of friction between the block and the surface.
\hfill \mbox{\textit{OCR M1 2009 Q4 [8]}}