A 380 kg piano slides 3.0 m down a 28 ∘ incline and is kept from accelerating by a man who is pushing back on it parallel to the incline. Ignore friction.

A)Determine the work done on the piano by the man.
B)Determine the work done on the piano by the force of gravity.
C)Determine the net work done on the piano.

Question

A 380 kg piano slides 3.0 m down a 28 ∘ incline and is kept from accelerating by a man who is pushing back on it parallel to the incline. Ignore friction.  

A)Determine the work done on the piano by the man.
B)Determine the work done on the piano by the force of gravity.
C)Determine the net work done on the piano.

anonymous · Answer

if it is kept from accelerating the it moves at constant speed, so there is no variation in kinetic energy: $\Delta K = 0$, because final and initial speed are the same.
the net work done on the piano must then be zero, since $\Delta K = W_{net}$ by the Work-Energy theorem.
can you find the work done by gravity?

anonymous · Answer

@Greg_D could you help me out with a separate problem?

anonymous · Answer

you should make a new post if it is adifferent problem, we better keep 1 question per post