| Exam Board | OCR |
|---|---|
| Module | M3 (Mechanics 3) |
| Year | 2008 |
| Session | June |
| Marks | 6 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Hooke's law and elastic energy |
| Type | Horizontal elastic string on smooth surface |
| Difficulty | Standard +0.3 This is a standard M3 elastic string problem requiring Hooke's law for part (i) and energy conservation for part (ii). The setup is straightforward with clearly given parameters, and both parts follow routine procedures taught in mechanics modules, making it slightly easier than average for A-level mechanics questions. |
| Spec | 6.02h Elastic PE: 1/2 k x^26.02i Conservation of energy: mechanical energy principle |
1 A particle $P$ of mass $m \mathrm {~kg}$ is attached to one end of a light elastic string of natural length 1.8 m and modulus of elasticity 1.35 mg N . The other end of the string is attached to a fixed point $O$ on a smooth horizontal surface. $P$ is held at rest at a point on the surface 3 m from $O$. The particle is then released. Find\\
(i) the initial acceleration of $P$,\\
(ii) the speed of $P$ at the instant the string becomes slack.
\hfill \mbox{\textit{OCR M3 2008 Q1 [6]}}