In this question use g=9.8g = 9.8g=9.8 m s−2^{-2}−2.
A block AAA, of mass 2 kg, rests on top of a block BBB, of mass 5 kg. Block B B\,B rests on a smooth horizontal floor.
The coefficient of friction between A A\,A and B B\,B is 0.4. A horizontal force of magnitude P P\,P newtons is applied to BBB. The blocks are modelled as particles.
Find the greatest acceleration with which the blocks can move together without A A\,A sliding on BBB.
Hence find the greatest value of P P\,P for which the blocks move together.
87 exam-style questions on OCR (MEI) A Level Maths 3.4 Forces, covering 3.4.1 Language relating to forces, 3.4.2 Acceleration due to gravity, 3.4.3 Identify forces and draw force diagrams, 3.4.4 Resultant of concurrent forces, 3.4.5 Equilibrium of a particle, 3.4.6 Resolve a force into components (A-level only), 3.4.7 Equilibrium condition for resultant zero (A-level only), 3.4.8 Forces in equilibrium sum to zero (A-level only), 3.4.9 Equations for a particle in equilibrium (A-level only), 3.4.10 Frictional force and normal contact force (A-level only), 3.4.11 Model friction with F ≤ μR (A-level only), and 3.4.12 Apply Newton's Laws to friction problems (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.