An object of mass m is at rest on a rough inclined plane with height h, length 8 m, and which makes an angle of 30° with the horizontal (figure below). The object is allowed to move down and it stops on a rough horizontal surface, at a distance of 4 m from the bottom of the inclined plane, as shown in the figure. The coefficient of kinetic friction on the inclined plane is Mk = 0.4
(a) Using conservation of energy, find the speed of the object at the bottom of the inclined plane?
(b) What is the coefficient of kinetic friction for the horizontal surface?