| Exam Board | Edexcel |
|---|---|
| Module | M3 (Mechanics 3) |
| Marks | 7 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Hooke's law and elastic energy |
| Type | Elastic string equilibrium and statics |
| Difficulty | Moderate -0.3 This is a straightforward two-equation system using Hooke's Law (T = λx/l) and equilibrium (T = mg). Students substitute given values, solve simultaneous equations for natural length and modulus. Standard M3 bookwork with clear structure and no conceptual surprises, making it slightly easier than average. |
| Spec | 6.02h Elastic PE: 1/2 k x^2 |
2. A light elastic string $A B$ has one end $A$ attached to a fixed point on a ceiling. A particle $P$ of mass 0.3 kg is attached to $B$. When $P$ hangs in equilibrium with $A B$ vertical, $A B = 100 \mathrm {~cm}$. The particle $P$ is replaced by another particle $Q$ of mass 0.5 kg . When $Q$ hangs in equilibrium with $A B$ vertical, $A B = 110 \mathrm {~cm}$. Find
\begin{enumerate}[label=(\alph*)]
\item the natural length of the string,
\item the modulus of elasticity of the string.
\end{enumerate}
\hfill \mbox{\textit{Edexcel M3 Q2 [7]}}