kinetic energy

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RE: Kinetic Energy

Postby Patriot » Thu Mar 26, 2009 11:14 am


What is considered ethical for deer?

I found the answer.

Paul K. "aim small, miss small"

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RE: Kinetic Energy

Postby Bowtechian » Thu Mar 26, 2009 1:26 pm

405 gr. @ 300 fps. = 80.96 ft./lbs. My 82nd Airborne has a few foot pounds to spare according to the chart.
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RE: Kinetic Energy

Postby MT_Bowhunter » Sun Apr 19, 2009 2:18 am

If I were going after Cap Buff and or Alaskan Brown or Alaskan Grizzly bears I would turn my bow up to 70# and have enough KE to spare @ 83.76 ft pounds.
"Bowhunting is like golf, you just can't use one club"

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RE: Kinetic Energy

Postby Bowtechian » Sun Apr 19, 2009 5:06 am

That's pretty impressive that you can get 294 fps. through a chronograph with a 436.3 gr. arrow. Didn't realize Drenalin's were that fast.
Dave M.

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RE: Kinetic Energy

Postby Wanderer » Thu Oct 15, 2009 5:27 am

I turned my Diamond Rock down to 53 pounds due to some back problems I've been experiencing lately. I was concerned about loss of kinetic energy, so last night I shot through the chronograph and found that I have 234 fps with a 418 grain arrow. That still gives me 53.88 ft/lbs of kinetic energy. That's plenty for deer hunting, so I feel better now.

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RE: Kinetic Energy

Postby turtle6776 » Sat Oct 24, 2009 9:07 am

How about instead of going to a page to type it in to do it for you just remember this equation SpeedXSpeed xweight ( grains) /450240= KE   that is the kinetic energy formula for you   its Speed in FPS squared x weight in grains divided by 450240 this gives you all you need to know

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RE: Kinetic Energy

Postby trapperDave » Sun Oct 25, 2009 2:59 am

HORSESPIT!  Aint never been a deer yet killed by KE. Sharp broadheads kill deer. The AVERAGE KE for trad  gear is in the 20's... and they've killed everything from mice to elephants ;)
that KE/Hunting usage graph is the dumbest crap I ever seen. want some eye opening study material? check it out...  testing using a 40# recurve on a buffalo (not bison, buffalo-the asian variety)
"Democracy is a lamb and two wolves voting on what to have for lunch; Liberty is a well armed lamb contesting the vote." Ben Franklin

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RE: Kinetic Energy

Postby CB on the run » Sun Oct 25, 2009 6:44 am

If we were just talking about traditional cut on contact broadheads then I would wholeheartly agree with you. However, when you throw in non-cut on contact mechanical broadheads that a lot of archers shoot, then KE becomes very important for penetration. IMO we still have to pay attention to KE depending on the individuals equipment.


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kinetic energy

Postby Lot to Learn » Thu Jul 15, 2010 7:10 am

I need some help here.  I keep reading speed does not matte kinetic energy does.  Two things make up kinetic energy, mass and speed.  So I am not understanding the statement.   I was also reading where the kinetic energy drops faster for a lighter arrow. Can anyone point me towards an article or anything where I can read up on this.  For KE to decrease the speed is the only factor that can decrease.  Unless I am just missing something, once the arrow is shot and until it hits a deer only two forces are acting on it, gravity and air resistance.   I am thinking both of those forces would effect a heavier arrow(all other things being equal) more than a lighter arrow. 

I know this is just academic, most of have energy to spare and we are most likely talking about how far the arrow is going to stick in the ground, but this has been bugging me and I would like to learn a lot more about it. thanks.

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RE: kinetic energy

Postby passin through » Thu Jul 15, 2010 7:59 am

This has been something I have been very interested in this year as well.  So far I have learned a little and to understand better, I country fried it[:D].  Basically the statement that speed doesn't matter is wrong, it does! But speed is more often seen as a constant since a given bow will only shoot so fast and you can always change up your arrow weight.  For example:  Take two vehicles--- a Toyota Camry and a Ford f350 diesel, both will do 100 MPH easily.  Say you hit a deer in both doing 100mph.  The damage done by the 1ton truck is a whole lot more severe and for the truck a whole lot more survivable.  Same can be said for heavier arrows.....they hit harder and are more forgiving at constant speed.... 
As for part 2 of your question.... same analogy to be used....It takes a lot longer to stop something heavy than something lite.  Simply because the force required to get it into motion must eventually equal the force to stop it. ie for every action there must be an equal and opposite reaction.  Or the force expounded by your bows limbs must eventually equal the force of gravity to slow it down.  A lighter arrow slows because it doesn't take as much to get it going in the first place.
It matters not the weapon nor its caliber, rather the caliber of the one who wields it.


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