Two blocks, each of mass m = 2.1 kg, are pushed along the horizontal surface of a table by a horizontal force P of magnitude 5.4 N, directed to the right, as shown in the figure below. The blocks move together to the right at constant velocity.
(a) Find the frictional force exerted on the lower block by the table.
(b) Find the coefficient of kinetic friction between the surface of the block and the table.
(c) Find the frictional force acting on the upper block.