Catching a wave, a 77-kg surfer starts with a speed of 1.2 m/s , drops through a height of 1.60 m , and ends with a speed of 8.5 m/s .

How much nonconservative work was done on the surfer?

1 answer

ok, I will do it all out

beginning Ke = (1/2)(77)(1.44)=
= 55.44 Joules

final Ke = (1/2)(77) (8.5)^2 = 2782 Joules

gain in Ke = 2782 - 55.4 = 2726 Joules

drop in Potential energy U = 77*9.8*1.6
1207 Joules

so 2726 -1207 = 1519 Joules came from something else non-conservative, like paddling