If an arrow starts losing speed, ie. energy, as soon as it leaves the string, then the KE is constantly dropping as the arrow continues it's flight, correct? So that to say you are shooting a certain speed bow in conjuction with a certain weight arrow so you have an arrow with "X" amount of KE is truly a misleading statement, right? If part of the formula for KE is arrow speed, and the arrow is constantly losing said speed, then in order to compare one bow/arrow combo to another as far as KE, the chrony would have to be the exact same distance from each bow, yes? So when the statment is made that you need, or should have, "X" amount of KE in order to use mechanical heads, or to hunt elk or whatever, "X" amount of KE at what distance?
By the way, I never took physics, and didnt always pay attention in class like I should have!!