A student, starting from rest, slides down a water slide. On the way down, a kinetic frictional force (a nonconservative force) acts on her. The student has a mass of 80 kg, and the height of the water slide is 13.0 m. If the kinetic frictional force does -7.7 × 103 J of work, how fast is the student going at the bottom of the slide? Use g = 9.81 m/s2