A crate of mass 10.6 kg is pulled up a rough incline with an initial speed of 1.48 m/s. The pulling force is 104 N parallel to the incline, which makes an angle of 20.1° with the horizontal. The coefficient of kinetic friction is 0.400, and the crate is pulled 5.05 m.
(a) How much work is done by the gravitational force on the crate?
(b) Determine the increase in internal energy of the crate-incline system due friction.
The Attempt at a Solution
I have solved part A, and I got -180 J. I need help on B. I really don't know what the question is looking for. Thanks