Two particles P P\,P and QQQ, of masses 3m kg and m m\,m kg respectively, are connected by a light inextensible string.
The string passes over a smooth fixed pulley, and both particles hang freely with the string vertical on both sides of the pulley.
The system is released from rest with the string taut.
Show that the magnitude of the acceleration of each particle is 12g\displaystyle \frac12 g21g.
Hence show that the tension in the string is 32mg\displaystyle \frac32 mg23mg.
139 exam-style questions on AQA A Level Maths 3.3 R: Forces and Newton's laws, covering 3.3.1 Concept of a force and Newton's first law, 3.3.2 Newton's second law, 3.3.3 Weight and motion under gravity, 3.3.4 Newton's third law and equilibrium, 3.3.5 Addition of forces and resultants (A-level only), and 3.3.6 Friction (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.