Probability — practice question

A uniform rigid rod $AB$ with length $1.2\,\text{m}$ and weight $8\,\text{N}$ carries a particle of weight $2\,\text{N}$ fixed at endpoint $B$. Endpoint $A$ is attached by a free hinge to a fixed point. One end of a light elastic string, whose natural length is $0.8\,\text{m}$ and modulus of elasticity is $20\,\text{N}$, is fastened to the hinge. The string passes over a small smooth pulley $P$ fixed $0.8\,\text{m}$ vertically above the hinge. The other end is connected to a small light smooth ring $R$ that can move along the rod. The system is in equilibrium, with the rod making an angle $\theta^{\circ}$ to the vertical (see diagram).