A rope is used to pull a 5.57 kg block at constant speed 2.78 m along a horizontal floor. The force on the block from the rope is 7.93 N and directed 31.6° above the horizontal. What are
(a) the work done by the rope's force,
(b) the increase in thermal energy of the block-floor system, and
(c) the coefficient of kinetic friction between the block and floor?