A 100-Kg Piano Rolls Down a 20° Incline

Multiple Choice

A 100-kg piano rolls down a 20° incline.A man tries to keep it from accelerating, and manages to keep its acceleration to 1.2 m/s².If the piano rolls 5 m, what is the net work done on it by all the forces acting on it?

A) 60 J
B) 100 J
C) 600 J
D) 1000 J
E) 4900 J