A 330 kg piano slides 3.60 m down a 28-degree ramp at constant speed, partially supported by a man who pushes upward, parallel to the ramp. The coefficient of kinetic friction between the piano and the ramp is 0.400.

Calculate:

a. force exerted by the man
b. work done by the man on the piano
c. work done by the friction force on the piano
d. the work done by gravity on the piano
e. net work done on the piano
Does the last answer make sense, explain briefly