ok. Let me say, this idea of an energy balance and KE is not "my theory". I am not near that intelligent. I can only present the facts. Let me start with the momentum and KE confusion.

KE is again 1/2mv^2. Momentum is m*v. Now in Calculus Momentum is consider a derivative of KE. This means that Momentum is actually a representation of the change in KE. Let me explain. AS KE energy decreases over a distance, say from 20 to 40 yards, then momentum is a rate of change. So as the KE energy changes, the momentum is a reprentation of that change. To say that momentum does not affect penetration is not what I am trying to say. What I am saying is that we have no mathematical way to relate mometnum and penetration directly. KE is the only way to represent the relationship of velocity, arrow wieght and penetration. Just like velocity is related to acceleration......momentum is related to KE. Velocity affects each one but in a different proportion. It is just a matter of how they relate to penetration. And by the way...all this can be proved mathematically. But trust me is sucks!!!!!


Now on the momentum aspect. Yes momentum has everything to do with deflection on bone or hard tissue. Remember momentum is not momentum without direction. As an arrow glances off a bone or breaks the bone, it is transfering momentum to the bone in a particular direction. This is the law of "conservation". Momentum is conserved.....always.!!!!!!! So Yes an arrow carries a certain amount of momentum and that is it. Once that is used up...no more momentum transfer. Also remember that momentum and KE will equal zero at the same time. So they are related.

I don't mean to confuse the matter. It is just that momentum and KE are so closely related the two get confusing some times.

Our best tool for judging penetration is KE. Sorry guys.....scientific principles.....I don't make the rules....I just learned how they are applied.

IF anyone cares this is the energy balance
All these terms actually represent a change between two points.

(v^2)/2 + g(z) + w + F = 0

v=velocity
g=gravity
w=work
F=friction

Verbally this reads

change in Kinetic energy + change in potential energy + work + friction = zero.