Thank god for physics[8D]

What is being said is momentum is what really determines penitration for an arrow, it is the resistance to change of velocy/direction (meaning what keeps the arrow moving through an animal).

Without getting technical, strait line momentum of an arrow is greater w/ high FOC. (Moments of Inertia anyone[&:]?) Therefore, high FOC is preferable. How great of a difference does FOC have? That is the question....

Kinetic Energy does not directly relate to penetrating ability for archery although it does have useful comparative properties.