In this question use g=9.8g = 9.8g=9.8 m s−2^{-2}−2.
A block of mass 12 kg is pulled up a rough plane inclined at an angle of 20° 20°\,20° to the horizontal by a force of magnitude P P\,P newtons acting up a line of greatest slope.
The block moves up the plane at a constant speed. The coefficient of friction between the block and the plane is 0.25.
Find the value of PPP.
The force is removed at an instant when the block is still moving up the plane. Find the deceleration of the block immediately afterwards.
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.