Yes. And, there's a program out that will show speed and KE at varying yardage. You can plug in the arrow, fletching, and how much the arrow weighs and it will spit those numbers out. Due to wind resistance, an arrow is slowing down immediately upon release.

U brought up a good point about some set ups not being very well.....I got to thinking about that, and I tend to look at everything in a 30" 70# world....but that's not accurate. I would think if you are shooting low poundage, or shooting a very low end compound that you just won't get the speed out of anyway, KE is definetly the more critical factor. I was merely stating that if you can get the speed, KE will be a natural product of that. Though it wont have the same momentum, and a light arrow will slow down faster than a heavy arrow......But like you said, most shots are 20 yards or less, so how much is really needed to kill a deer?