This is what I'm talkin about!

[royden]

So it ain't theoretical - the arrow has already left the bow.

The only energy drains that would then affect the arrow such as noise, friction, porpoising, flex are not taken into account by either method. Hmmm

[michihunter]

True. To a degree. The other aspects of energy are somehow figured in although you cannot pick each particular part of that "energy" apart as you can momentum which ONLY relies on mass and speed. Another thing you may take into account is the fact that scalar is part of a vector quantity. Meaning that vector is scalar with direction. So it is "more" defining than KE. In the end, it is not wise to seperate the two but embrace them as a team to define the force being applied.

[BT]

No
K.E. is a measurement that can be seen while momentum is not.
While actual K.E. figures can be recorded by use of a chrono and weight scale , there is no such way to get a certain calculation of momentum.
Momentum is total therory without the means to check.

This is what drives most people crazy.

[michihunter]

Excuse me BT but by definition you are not right. Momentum can be measured the same as KE. Momentum= Mass x speed. KE = mv 2. You can get the resultsfor both by the same method of chrono and mass.

Here's some key components to back up my a$$ertion. These are staight from physics research guides.

A system observable is a property of the system state that can be determined by some sequence of physical operations. Examples of observables include energy, position, momentum, and angular momentum.
Observable here is used in the strictest form of Physics and can be found with a simple search. Might want to show that student site these findings BT!! ;D ;D

[BT]

I knew I could keep this going ;D

Here....proffessor of physics , batesville college

jerry stanbrough

[e-mail]

You can debate him for awhile

[michihunter]

What fun is that? Present FACTS BT. That's all. I've done so at every turn. Back up your "theory" that momentum is nothing more than just "theory". ;)I have done otherwise. When I tire of you, I'll go see Mr. Stanbrough but only if you go debate Dr. Ken Mellendorf ;D ;D
Physics Instructor
Illinois Central College
[e-mail]

as well as
S. Auyang, How is Quantum Field Theory Possible, Oxford University Press, 1995.
G. Mackey, Mathematical Foundations of Quantum Mechanics, W. A. Benjamin, 1963.
V. Varadarajan, The Geometry of Quantum Mechanics vols 1 and 2, Springer-Verlag 1985.

Those are the people that will tell ya that Momentum is indeed observable.
;D ;D

[BT]

I hear you
I have supplied facts throughout .... with the exception of supporting the claim that the momentum theory is one that cant be proven.
But as I have also said....the K.E. equation is also suspect and therefore under question.
These methods are based on fact but nothing can be built around these methods to prove out anything.
Suggestive at best.

What is so hard for anyone to wrap their heads around is speed.
Weight is easy....we have all dropped things on our toes and it hurts like hell.
But nobody living has thrown themselves into the floor at 300 miles and hour

If this occurrence were as common as our dealing with weight , I am sure more people would have the imagination to envision speed as being deadly

O.K. .... I'm done ... read that as tired .... good one Michi

[fjasso]

Kinetic energy is the amount of energy the arrow has in ALL directions: spinning, vibration, friction etc. It is the amount of energy the bow transfers to the arrow.Faster arrows has more energy (I repeat, in all directions).
Momentum is the amount of energy the arrow has in the direction in which it is traveling. It is theenergy the bow transfers the arrow twords the target direction. It only considers the energy in the same vector the arrow is going therefore it is much better and it will have more punch and penetration if you have more momentum than KE.

The train vs motorcycle comparison. I´d rather be hit by a high speed motorcycle

[bowhunter44]

WOW! Quite the read, and fascinating to boot. I wish there had been a conclusion at the end

An observation (or something akin to an observation):

Total Energy - it has long been my impression that the total energy of an object was the sum of all the energy components of the object - kinetic energy, potential energy, heat, sound, the works. The name associated with the total energy, as I understand it, is Mechanical Energy (not kinetic energy). The total kinetic energy, on the other hand, would be the sum of all of the components of the motion of the object (linear motion, rotational motion, vibration.....).

I wonder.... The word force doesn't show up in the KE vs. momentum debate - ever. Why not, he wonders? It would seem to me that the force of the projectile shoul be as significant to the penetration of the projectile as any other parameter. Maybe more appropriate than force would be the impulse of the object (the amount of force applied by the object and time over which the force is applied).

Force (or impulse), like KE and momentum, is a function of both mass and veloicty (although the velocity component of force is tangled up in the acceleration of the object).

I'm about to give myself a headache.... Thoughts of two projectiles with the same force impact a target, one with a more significant mass contribution to the force, the other with a more signification acceleration contribution to the force......

[BT]

The observation and conclusion are self evident for me and it was stated in the first post.
Michihunter was a great guy to bounce things off for the benefit of the viewers
The fact remains that what was said in the opening post are the facts and indisputable.

Back 20 years ago I spent more time than I do now on archery and I was all about penetration, flight and head design.
Nothing else really mattered to me.
This is where I came to find many variables and many constants and I use those findings to this day.
My bottom line is that as long as you are over 300fps and inside the flat flight of the arrow, with the appropriate head ( 1 1/2" or smaller & Passing tests) it doesn't matter what your hitting on a whitetail....your going to kill that deer if there are vitals on the other side.

The real questions and manipulations start at speeds below 300 and this is where head size, type and design start becoming more important.
At speeds below 280, you are starting to consider the arrow as well.

I strive to achieve speed first, in order to eliminate as many of those variables as possible.