Energy, work and power — practice question

Particles $A$ and $B$, having masses $2\,\text{kg}$ and $3\,\text{kg}$ respectively, are joined by a light inextensible string. Particle $B$ rests on a smooth fixed plane inclined at $18^\circ$ to the horizontal ground. The string goes over a fixed smooth pulley at the top of the plane. Particle $A$ hangs vertically beneath the pulley and is $0.45\,\text{m}$ above the ground (see diagram). The system is released from rest while the string is taut. When $A$ reaches the ground, the string breaks.