9709 P43 - Nov 2014 - Q2
The tops of each of two smooth inclined planes A and B meet at a right angle. Plane A is inclined at angle \(\alpha\) to the horizontal and plane B is inclined at angle \(\beta\) to the horizontal, where \(\sin \alpha = \frac{63}{65}\) and \(\sin \beta = \frac{16}{65}\). A small smooth pulley is fixed at the top of the planes and a light inextensible string passes over the pulley. Two particles P and Q, each of mass 0.65 kg, are attached to the string, one at each end. Particle Q is held at rest at a point of the same line of greatest slope of the plane B as the pulley. Particle P rests freely below the pulley in contact with plane A (see diagram). Particle Q is released and the particles start to move with the string taut. Find the tension in the string.
