RE: Arrow penetration vs. weight
Yup TFOX, that is right (at least to the best of my understanding, and besides that you are always right!!). As velocity increses the frictional force, in fact,decreases.
Roskoe also has a good point about penetration of tissue. I read the other daythat when an arrow penetrates an animal, the flesh has a tendancy to withdraw from the shaft.However, when penetrating a target the opposite is true.
I hope this doesn't turn into a 40 page nightmare too!