A 390 kg piano slides 2.6 m down a 27 ∘ incline and is kept from accelerating by a man who is pushing back on it parallel to the incline. ignore friction.
a) Determine the force exerted by the man.
b) Determine the work done on the piano by the man.
c) Determine the work done on the piano by the force of gravity.
d) Determine the net work done on the piano.