Drag on a Skydiver?

Question

A skydiver of mass m jumps from a hot air balloon and falls a distance d before reaching a terminal velocity of magnitude v. Assume that the magnitude of the acceleration due to gravity is g. What is the work Wd done on the skydiver, over the distance d, by the drag force of the air?
Express the work in terms of d, v, m, and the magnitude of the acceleration due to gravity g.
And Find the power Pd supplied by the drag force after the skydiver has reached terminal velocity v.

Answer 1

Use the work energy theorem:
KE = 1/2mv^2.
PE = mgh = mgd (no not Miller Genuine Draft) but mass * gravity * distance

but the skydiver is fallling, so:
Work = 1/2mv^2-mgd

Power = F dot v (if vectors), so, if F = ma = mg and the direction is negative, then P = -mgd (don't forget the negative sign due to gravity).