2 arrows of different mass but the same KE = same penetration????

[jrchambers]

raideranch i agree with that completly, i was saying in a fantisy world where gravity doesnt play just friction from the air that the heavy one would decelerate slower and in theory catch up. this could never really happen,
look at it this way two arrows different weight, same speed and angle, they both will hit the ground at the same exact time but the heavy one will travel further due to the greater retained momentum,  penetration is limited by friction as is trajectory,  more mass = more momentum wich friction effects slower.

I hope you understand my ramble
hey ani gravity arows would be nice though

[raideranch]

Yea I understand what you're saying and that's why I like heavier arrows.   Heavy arrows are more stable because it takes more force to move them off path.

[Richie Nell]

The lighter, faster arrow may travel a longer distance in a given time but upon resistence (including air, target, deer) it will slow quicker than the heavier arrow resulting in less penetration.  Even though the heavy arrow starts slower, its mass allows it to keep moving upon resistence resulting in better penetration.

That is why Mass is King...not speed.  

If you are in a traffic accident...do you want to be in a Prius or a Landcruiser?

[Ragnarok Forge]

A law of physics states that a body in motion tends to stay in motion.  The same law / principle applies to the fact that a heavier body will stay in motion longer than a lighter body when they meet equal resistance.  Pretty simple answer to the question.  Physicists already solved it for us.

[raideranch]

"when they meet equal resistance"

True, but if the lighter arrow arrives at the target faster there is less time for the "resistance" (gravity, wind, etc...) to act on it so do they have equal resistances?

[Richie Nell]

Probably wrong here but excluding the target at the end of flight, I would think the lighter arrow would have less actual resistence flying (time wise) but affected more as in slowing faster.  The heavy arrow would have more resistence (time wise) but affected less because of its mass.

Oh boy.  I'm clueless.

[jrchambers]

as far as wind goes the faster would have less resistance. and the longer the arow is in flight the more gravity affects, but i dont know if gravity is resistance,
now as far as O2 friction i would tend to think that regardles of speed the same amount of friction would aply to each arow over a equal distance travled.     regardles of how fast or slow a arow travles through the air it still has to travel through the same amount, excluding wind.
just a thought what if speed did create more friction, like a piece of sandpaper drug across a board fast then slow with the same pressure, the faster it is moved the more heat is created wich is a indicator of friction.

[ozy clint]

jrchambers- you just contradicted yourself.

sure the two arrows pass through the same amount of air but the faster one encounters more air resistance. that's why the fast sand paper creates more heat even with the same pressure as the slow sand paper.

[Jeff Strubberg]

It's a law of physics that doubling speed produces four times the resistance.  That applies equally to arrows or airplanes.

Also, that law applies regardless of whether you are travelling through air or a game animal.

[jrchambers]

oh so i did,  well done quite a bit of thinking about the origonal question,  i belive the answer would be no they could not penetrate equal.  If the lighter arow was 550 going 190 right off the bow and the other was 650 going 180, thats a diference of 10fps right off of the bow, and say just for giggles there KE is the same, I know its not in that scenario but when they hit a target at 20 yards the difference in speed is not going to be 10fps it would be less I dont know how much but the KE of the heavy one would be greater.  to have the same KE at the point of impact would reqire a bit more from the lighter arow at the bow and then once more resistance hits the two arows the lighter one would loose speed, KE, and momentum even faster then when in flight,  
just the way i see it

[Don Stokes]

Unless it was a very small coconut, I think it would probably take at least FOUR African swallows...

[ChuckC]

Jr I am guessing that the faster arrow likely has the higher KE, since the speed factor is squared.

All this and what did we decide ?  Will either arrow fill a deer ?
ChuckC

[ChuckC]

Jr I am guessing that the faster arrow likely has the higher KE, since the speed factor is squared.

All this and what did we decide ?  Will either arrow kill a deer ?
ChuckC

[Jason R. Wesbrock]

Originally posted by Don Stokes:
Unless it was a very small coconut, I think it would probably take at least FOUR African swallows...

It could grip it by the husk.   :D

[raideranch]

"It's a law of physics that doubling speed produces four times the resistance"

This has been posted like 10 time but we aren't talking about doubling the speed.  We're on only talking about increasing it 10-15 fps at the most in a hunting arrow.  This "law of physics" doesn't apply at all velocities.

[Guru]

After 4 pages, all this is proving...what?      

[lpcjon2]

That we like to type about things that we will never be able to prove or find any facts to prove anything.

[Jason R. Wesbrock]

Originally posted by Guru:
After 4 pages, all this is proving...what?        

That a few of us apparently watched too many Monty Python movies.  

[Mooseandbuck44]

Here is a link where you can plug in arrow speed, weight, and other characteristics and it will generate arrow drop, speed, KE, and momentum at different distances:

http://home.att.net/~sajackson/ballistics.html

[Jeff Strubberg]

Originally posted by raideranch:
"It's a law of physics that doubling speed produces four times the resistance"

This has been posted like 10 time but we aren't talking about doubling the speed.  We're on only talking about increasing it 10-15 fps at the most in a hunting arrow.  This "law of physics" doesn't apply at all velocities.

Uh, it applies at every velocity.  It applies to arrows, apples and airplanes.  

As far as proving anything, nah.  Just shooting the breeze...