Maths with David

    9709. M1. Friction. Past Exam Questions

    9709/41/M/J/25q1 – Mark Scheme

    A block of mass 12kg is being pulled by a rope up a rough plane. The plane is inclined at an angle of 20º above the horizontal. The rope pulling the block is parallel to a line of greatest slope of the plane. The coefficient of friction between the block and the plane is 0.4. The acceleration of the block is 2 ms-2.

    Find the tension in the rope. [4 marks]

    9709/42/F/M/25q6 – Mark Scheme

    A block of mass 12kg is placed on a rough plane inclined at an angle of \alpha to the horizontal, where \alpha = tan^{-1} 0.5 . A force of X N is applied to the block, directly up the plane (see diagram). The coefficient of friction between the block and the plane is \mu .

    (a) It is given that \mu = 0.15 and X = 20.

    Find the time that it takes for the block to move 2m down the plane from rest. [6 marks]

    (b) It is given instead that \mu \neq 0.15 and that when X = 10, the block is on the point of moving down the plane.

    Find the value of \mu and the value of X for which the block is on the point of moving up the plane. [4 marks]

    9709/41/O/N/24q6 – Mark Scheme

    A particle of mass 1.2kg is placed on a rough plane which is inclined at an angle of \theta to the horizontal, where sin \theta = \frac{7}{25} . The particle is kept in equilibrium by a horizontal force of magnitude P N acting in a vertical plane containing a line of greatest slope (see diagram). The coefficient of friction between the particle and the plane is 0.15.

    Find the least possible value of P. [6 marks]