A non-uniform rod AB AB\,AB has length 200 cm and mass 15 kg. A particle of mass 10 kg is attached at CCC, where AC=40AC=40AC=40 cm. The rod is held horizontally by two vertical light inextensible strings attached at A A\,A and BBB. The tension at A A\,A is 10 N greater than the tension at BBB.
Given that g=9.8g=9.8g=9.8 m s−2^{-2}−2, find, to the nearest centimetre, the distance of the rod's centre of mass from AAA.
53 exam-style questions on OCR A Level Maths 3.4 Moments (A-level only), covering 3.4.1 Moment of a force (A-level only), 3.4.2 Equilibrium of a rigid body (A-level only), and 3.4.3 Moments in static contexts (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.