The surfer in the photo is catching a wave. Suppose she starts at the top of the wave with a speed of 1.45 m/s and moves down the wave until her speed reaches 10.1 m/s. The drop in her vertical height is 3.00 m. If her mass is 51.6 kg, how much work is done by the (non-conservative) force of the wave?
change of potential energy = m g delta h = 51.6 * 9.81 * -3 = -1519 Joules
increase in kinetic energy = (1/2) 51.6 (10.1^2 - 1.45^2) = 2500 Joules
so work done by wave is 981 Joules