2
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Particles \(A\) and \(B\), of masses 0.35 kg and 0.15 kg respectively, are attached to the ends of a light inextensible string. \(A\) is held at rest on a smooth horizontal surface with the string passing over a small smooth pulley fixed at the edge of the surface. \(B\) hangs vertically below the pulley at a distance \(h \mathrm {~m}\) above the floor (see diagram). \(A\) is released and the particles move. \(B\) reaches the floor and \(A\) subsequently reaches the pulley with a speed of \(3 \mathrm {~m} \mathrm {~s} ^ { - 1 }\).
- Explain briefly why the speed with which \(B\) reaches the floor is \(3 \mathrm {~m} \mathrm {~s} ^ { - 1 }\).
- Find the value of \(h\).