A tow rope, parallel to the water, pulls a water skier directly behind the boat with constant

Question:

A tow rope, parallel to the water, pulls a water skier directly behind the boat with constant velocity for a distance of 72 m before the skier falls. The tension in the rope is 140 N.
(a) Is the work done on the boat by the rope positive, negative, or zero? Explain.
(b) Calculate the work done by the rope on the boat.