A 57-kg water skier is being pulled by a nylon tow rope that is attached to a boat. The unstretched length of the rope is 11 m and its cross-sectional area is 2.0 10-5 m2. As the skier moves, a resistive force (due to the water) of magnitude 120 N acts on her; this force is directed opposite to her motion. What is the change in the length of the rope when the skier has an acceleration whose magnitude is 0.90 m/s2?