2 1. A rough plane is inclined to the horizontal at an angle α , where tan α = 3 4 A brick P of mass m is placed on the plane. The coefficient of friction between P and the plane is μ Brick P is in equilibrium and on the point of sliding down the plane. Brick P is modelled as a particle. Using the model, (a) find, in terms of m and g, the magnitude of the normal reaction of the plane on brick P (2) (b) show that μ = 3 4 (4) For parts (c) and (d), you are not required to do any further calculations. Brick P is now removed from the plane and a much heavier brick Q is placed on the plane. The coefficient of friction between Q and the plane is also 3 4 (c) Explain briefly why brick Q will remain at rest on the plane. (1) Brick Q is now projected with speed 0.5 m s−1 down a line of greatest slope of the plane. Brick Q is modelled as a particle. Using the model, (d) describe the motion of brick Q, giving a reason for your answer. (2) _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________