| Exam Board | OCR |
|---|---|
| Module | M4 (Mechanics 4) |
| Year | 2009 |
| Session | June |
| Marks | 6 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Circular Motion 1 |
| Type | Angular kinematics – constant angular acceleration/deceleration |
| Difficulty | Moderate -0.8 This is a straightforward application of constant angular acceleration equations (rotational analogues of SUVAT). Part (i) uses ω² = ω₀² + 2αθ to find α directly, and part (ii) uses θ = ω₀t + ½αt² to solve a quadratic. The question requires only routine substitution into standard formulae with no conceptual challenges or problem-solving insight. |
| Spec | 6.05a Angular velocity: definitions |
1 A top is set spinning with initial angular speed $83 \mathrm { rad } \mathrm { s } ^ { - 1 }$, and it slows down with constant angular deceleration. When it has turned through 1000 radians, its angular speed is $67 \mathrm { rad } \mathrm { s } ^ { - 1 }$.\\
(i) Find the angular deceleration of the top.\\
(ii) Find the time taken, from the start, for the top to turn through 400 radians.
\hfill \mbox{\textit{OCR M4 2009 Q1 [6]}}