A person can become too scientific to the point that what is normally a simple given, based on historic standards, becomes very confusing.

My simplistic interpretation of KE vs. momentum is:

1. KE is velocity derived from energy transmitted by the bow.
2. Momentum is force derived from the weight of the shaft.

Properly combine the two and you have more than enough to do the job.

A 40# bow, stick or compound, shooting a shaft having recommended minimum of 425-450 grain weight will efficiently do the job on a Whitetail. Therefore, Lower energy (slower) bows are assisted by heavier shafts (momentum = force attained from weight) and cut-on-contact heads.