In this question use g=9.8g = 9.8g=9.8 m s−2^{-2}−2.
Two blocks PPP, of mass 5 kg, and QQQ, of mass 3 kg, rest in contact with each other on a rough horizontal floor.
A horizontal force of magnitude 40 N is applied to PPP, pushing both blocks along the floor. The coefficient of friction between each block and the floor is 0.2.
Find the acceleration of the blocks.
Find the magnitude of the force exerted by P P\,P on QQQ.
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.