Neco Model Questions Vol1 2018 Physics Question 5

A block of mass 5.0 kg is released from rest at the top of a 4.0 m long smooth incline that makes an angle of 30° with the horizontal. The block slides down the incline and reaches the bottom with a speed of 3.0 m s⁻¹. The coefficient of kinetic friction between the block and the incline is not given. (a) Determine the coefficient of kinetic friction (μ) between the block and the incline. (b) Calculate the total work done by the frictional force during the descent. (c) The block is then attached to a motor that pulls it up the same incline at a constant speed of 2.0 m s⁻¹. The motor supplies a constant pulling force equal to the component of the block’s weight parallel to the incline plus the frictional force opposing the motion. Calculate the power output of the motor.