It obviously takes some energy to push an arrow through hide, flesh, and internal organs. A very sharpbroadhead with a COC design and a narrower cut takes less energy to accomplish this than a dull broadhead with a chisel point and a very wide cutting profile.

But the energy involved here is peanuts compared to energies in the firearms world. A 30/30 Winchester, agood short rangedeer caliber, produces about 2,000 foot pounds of kenetic energy. The .300 Winchester, a good solid elk rifle, has about 4,000 ft. lbs. Even the lowly .22 Long Rifle has more KE than most bows.

The whole energy thing may be somewhat misunderstood in rating both bows and firearms, though. The bottom line is that the size and shape of the wound channel is what kills game. The KE figures can only give you an idea of sort of potential the projectile has to inflict the wound - there are other significant variables as well. With the bow, the broadhead cuts a swath(s) of a certain size and depth of penetration. I have never heard this argued on this board, but I would venture that a pass through on game with a 55 lb. bow does not kill any better than a pass through with a 70 lb. bow - all other variables being equal. The 70 lb. just shoots a little flatter.