Solve the all parts of given problem:
Problem: A block of 8kg is being pushed to the left on a horizontal surface. The forces which act on the block are gravity, the normal force exerted by the surface, the kinetic friction exerted by the surface, and the pushing force. Point B is 6m to the left of point A. If the block is pushed with a force of 50N, and increases its speed from 2 m/s at point A to 6 m/s at point B, what was the work done by friction?
Please show the work for the calculation so I can understand what I'm doing. Thanks!