Waec Model Questions Vol1 2023 Physics Question 5

A 5.0 kg block is released from rest at the top of a smooth inclined plane that makes an angle of 30° with the horizontal and is 8.0 m long. At the bottom of the incline the block reaches a horizontal rough surface whose coefficient of kinetic friction is 0.20. The block continues to move on the rough surface and comes to rest after travelling 2.0 m. A constant horizontal force is applied opposite to the direction of motion during this 2.0‑m travel. (a) Calculate the work done by gravity while the block descends the incline. (b) Calculate the work done by the frictional force on the rough surface. (c) Determine the magnitude of the constant horizontal force required to bring the block to rest exactly after the 2.0 m travel. (d) Find the average power delivered by this horizontal force during the motion on the rough surface.