Can someone do a quick calculation converting grams of drag to power needed to overcome that drag?

the equation reads

P = F v (of what?) = 1/2 x fluid density x (fluid velocity)^2 x CdA x velocity (of what?).

1st question. The drag in grams should actually be multiplied by gravitational acceleration, so it gives a reading of force. Does this mean the drag already accounts for fluid velocity?

2nd question. So say you are rolling along at 25mph into a 2mph wind, which velocity do you put in for the F v part?