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3 Things You Should Know About Kinetic Energy in Archery

If you've ever heard of kinetic energy in archery and wonder what all the fuss is about, here are the top 3 things you need to know.

[caption id="attachment_6368" align="aligncenter" width="300"]Understanding kinetic energy in archery is important for a variety of reasons.  Image via Pixabay. Understanding kinetic energy in archery is important for a variety of reasons.
Image via Pixabay.[/caption] As a high school teacher I often get questions, comments, glances, and subtle expressions asking the eternal question, "When am I ever going to use this in my life?" True, you'll probably never need an instant recall of certain things you learn in school like finding the area of a circle, the date of the WWI armistice, or identifying the subject and predicate of a sentence. If you've been out of high school long enough though, you'll probably recognize how many things actually crop up in your life you learned in school. This brings us to the subject of kinetic energy. Kinetic energy in archery is widely discussed and constantly expounded upon. It is something we all probably learned the basics of in high school and understand the general idea. For archers, understanding this concept better can help us comprehend what happens when our arrows fly through the air and collide with an object. It can make us better and more ethical hunters as well. If you are an archery newbie, or a veteran who finds this stuff interesting, here are the top 3 things you need to know about kinetic energy in archery.

What is kinetic energy?

First off we need to get to the bottom of what kinetic energy is. Kinetic energy is a term that physicists use to describe the energy an object has while in motion. Understanding kinetic energy in archery is important because when our arrows impact game animals they must have enough energy to penetrate that animal. Visit any archery forum discussion on the subject and you are sure to run into differing opinions on the subject of kinetic energy. Truth be told, this subject has been debated ad nauseam across the internet. Some folks argue kinetic energy is important while others argue momentum is really the force that is important. The two terms are different, though related. If you increase the kinetic energy of an arrow it will have more energy when it gets to the target, this means more energy can be transferred to the target. If you increase the momentum of an arrow it means the arrow will have more ability to continue through things such as skin, fat, meat, and bone. Simply put if you increase either the kinetic energy of your bow or the momentum of your bow it will increase the killing power. For the average archer shooting a compound bow or crossbow your chief concern will lie with kinetic energy, while traditional shooters can focus more on the momentum of their arrow.

How to increase kinetic energy?

To understand how to increase kinetic energy you have to know the equation for determining it. The formula is as follows: “1/2 Mass times velocity squared” or “KE = (1/2 M) x (V2)” This means if you want to increase the kinetic energy of an arrow the simplest way to do so is to increase the speed at which the arrow is traveling. This is where today's ultra fast compound bows and crossbows come into play. Here is an example to illustrate the point. If I had a bow shooting a 400 grain arrow at 185 feet per second my kinetic energy would be 30.4 foot pounds. Now take the same bow and shoot a 900 grain arrow. This is a huge jump in arrow weight and requires special tubing, inserts, or filling if you are using carbon arrows. With this new heavy setup you will now be delivering 68.4 foot pounds of energy (On a side note, the momentum also increases as well). That is a pretty impressive jump and will no doubt ethically take down most animals you will encounter. [caption id="attachment_6367" align="alignright" width="194"]An modern bow like the PSE Bow Madness 30 combined with an average arrow will deliver enough kinetic energy for almost any animal you will ever hunt. An modern bow like the PSE Bow Madness 30 combined with an average arrow will deliver enough kinetic energy for almost any animal you will ever hunt.[/caption] But to get an idea of how to increase kinetic energy imagine we swapped out bows instead of arrows. Now we will shoot the first 400 grain arrow at 300 feet per second instead. This is a pretty average setup for modern compound bow hunters. If you plug in the information you'll find the arrow now is carrying 79.9 foot pounds of energy with it as it flies down range. All of this helps to aide in penetration. With modern compound cams and crossbows it is easier to increase the arrow speed rather than arrow weight. Traditional shooters cannot increase their velocity as easily, so they tend to focus on increasing their momentum which also allows them to kill animals ethically. Here is a handy kinetic energy calculator to help you get an idea of what your setup is producing.

How much kinetic energy do I need to hunt?

Here is where understanding kinetic energy in archery really comes into play. To ethically hunt an animal, your bow and arrow setup should meet some minimum kinetic energy requirements. Here is a good chart identifying the kinetic energy you should use when hunting different game. If you take the time to brows the chart you can see most modern setups will put you in the range for ethically taking animals you are likely to hunt. Many exotic hunters do opt for special heavy duty arrows and bows on dangerous game, and for some species it is required. On a final note when discussing kinetic in archery we can see that by increasing speed you can readily increase kinetic energy. That being said, archers with traditional bows can more easily making their hunting rig ethical by increasing arrow weight, thus increasing momentum. At the end of the day if you are shooting an average setup by today's standards you are likely delivering an adequate amount of kinetic energy upon the shot. If you want to improve your kinetic energy for any reason the easiest way to do so is increase your bow speed.

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NEXT: THE TRUTH ABOUT ARROW PENETRATION; PT 1 DR. ED ASHBY

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