posted by Jane .
A 66-kg water skier is being pulled by a nylon (Young's modulus 3.7 x 109 N/m2) tow rope that is attached to a boat. The unstretched length of the rope is 20 m and its cross-section area is 2.8 x 10-5 m2. As the skier moves, a resistive force (due to the water) of magnitude 180 N acts on her; this force is directed opposite to her motion. What is the change in length of the rope when the skier has an acceleration whose magnitude is 0.62 m/s2?
Lf - Li = F Lo/YA
I'm guessing they want net force
ma + 180
plug and solve