please help me with this energy problem?

Question

Catching a wave, a 83 kg surfer starts with a speed of 1.3 m/s, drops through a height of 2.05 m, and ends with a speed of 8.2 m/s. How much nonconservative work was done on the surfer?
J

Answer 1

the final kinetic energy is equal to the starting kinetic energy plus the loss if potential energy less the frictional loss

.5*83*8.2^2=
.5*83*1.3^2+
83*9.81*2.05
-Fwork

Fwork=83*(.5*(1.3^2-8.2^2)+
9.81*2.05)

=-1051 J

This shows that energy was added to the system - must be some energy from the wave

j