Whether for war, food, or sport, archery has been employed the world over. From China to Canada, Turkey to Thailand, all countries and peoples of the world have at one point practiced archery. However, with the advent of gunpowder, archery has seen a major drop in both its use and its usefulness. A major motive force for countries is military technology, and once guns became widespread and widely available, archery was no longer a viable military option. A motivating force for individuals which is even greater than squabbles between countries is this: getting food on the table. With access to guns, which require much less practice to use with deadly effect, the common people could then hunt game far easier than if they were using a bow and arrows. Of course, there are people who hunt game with bow and arrows for sport, and they will tell you the benefits of it over guns, but these are people who have been trained in the use of bows and arrows. A poor rural peasant in Russia in the 1800's spends much of his time toiling in the field, and he simply doesn't have the time nor the inclination to master the use of a weapon which...
1. Requires great skill to manufacture and maintain
2. Has a limited range
3. Often times cannot kill game immediately, requiring the pursuit of the injured animal until it succumbs to its wounds.
The net effect of the modern advent of gunpowder is this: archery is no longer used in either war or in feeding ones family (this is true in modern societies, which includes the vast majority of the world’s population). Therefore the only area that is left to archery is sport, which includes firing at animals as well as targets. Since being able to go to war with others (or at least defend oneself) and feed oneself are both necessary, and sport is not necessary, any people who are struggling (whether through conflict or famine) don’t have the time or the inclination to engage in archery. However, archery is still practiced as sport where it is a part of a peoples history and culture, and/or where people have the time and/or money to entertain themselves with it. It is in this area that archery has seen a rise in recent years.
With the industrial revolution and the development of the first world, many people have something known as “free time.” Throughout human history, for the vast majority of people, this was a concept completely foreign to them. However, in modern times even the poor are so much better off than human beings before 1800 CE that many of them as well have free time. Thanks also to the modern development of Liberalism, people also have something which was foreign to our forefathers: the freedom to choose what they want to do. There are so many choices a person can make, it can be staggering at times. Even with all the other things people could be doing with their free time, some inevitably choose archery. The question is, why? So far, I have done little to talk about archery beyond saying that it is obsolete and only tribal societies and people with free time still do it. But wait! There are some good points to archery! In fact, I would say that if you had to choose an anachronistic pastime to engage in, archery may very well be the best option.
Archery is tied in with the culture of many people, such as Japanese, Native Americans, Mongolians, Tibetans, Welsh, Turkish, etc. If you belong to such a group, or want to learn more about them, archery is a great way to get in touch with a peoples culture and history.Even if you have no culture inclination to practice archery, there is a reason it is the fastest growing sport in the US. Archery is a sport which can be easily learned, but take years to master. There is nothing like training at something and becoming good at it. The source of true self confidence is working hard at something, and succeeding. Archery may seem hard at first, but with a consistent form, and a steady arm, anyone can succeed at archery and feel the elation that comes from hard work and success.
Archery is something that at one point or another, all of mankind has had in common with each other. There are many different styles of archery, bows, and arrows, but even with such differences they all have a few things in common.
1. A bow, made from metal, plastic, carbon composite, wood, or bone.
2. Arrows, made from much the same substances, with the purpose being to fly straight and far and embed in something.
3. A bow string, made from artificial materials, intestine, or hide, with the purpose being to hold the bow taut, so that there is a certain amount of potential energy when the string is pulled back before being released.
Now that the similarities have been identified, I shall now identify differences between different styles of bows and arrows. There are three main types of bow, recurve, longbow, and compound bow.
The recurve bow comes from the bow used by nomadic peoples throughout Asia, most famously by the Mongolians. There is a reason the bow cut such a devastating swath through China, central Asia and Europe. It is made by taking the bow material and bending it backwards, such that there is far more tension in the bowstring than a longbow of similar size.
The other type of bow, a longbow, is bent going with the bend of the material, so that the material is under much less tension that a recurve bow, but it also has less power than a recurve bow. This style of bow was used throughout Europe. To give the European archer the power to kill from long distances, he used a bow that was quite large, around 5-6 feet in length (or, about equal to the height of the archer). This prevented him from using on horseback, so that any European horse archers had to use a short bow ( don’t be fooled by the name, it is a “longbow,” but is much shorter), which was similar in size to the Mongolian recurve bow, but since it wasn’t bent in the recurve fashion, it had much less power than its eastern counterpart. While the Europeans solved this problem by avoiding it all together and just using infantry archers, the Japanese found a creative solution. The reason one couldn’t use a longbow on horseback is because the bottom half of the bow is far too long to be able to move the bow from one side of the horse to another. The Japanese longbow has the handle farther down the length of the bow, so that rather than holding onto the bow in the middle, you hold onto it about 2/3 of the way down the bow. This makes it so you can keep the power of a longbow, while still using it on horseback.
A (crude) drawing of a piece of wood being bent to form a longbow on top, and a recurve bow on the bottom. The recurve bow is bent more, so it possesses more power when it fires an arrow.
A compound bow is a modern revamping on the old bow. It is something that you could hardly guess is a bow upon first glance, looking like some sort of metal thing with a series of pulleys and multiple strings. This bow has taken our knowledge of mechanics and used it to create a machine which multiplies the force a human can exert beyond that of either a six foot longbow or a backwards-bent recurve bow. It has very interesting properties concerning the force required to use it. When you pull back far enough on a compound bow, the pulley mechanism kicks in and all of a sudden, the force you have to exert on it decreases drastically. You pull back, it gets heavier as you pull farther, then at a certain point it becomes very easy to pull back. While it becomes easy to pull back at this point, it in no way diminishes the force that will be exerted on the arrow when it is fired. This force is often far too great for target shooting, as it can embed an arrow into the target and make it difficult to pull out. As such, it is used more for hunting than in competitive archery.
A bow can be thought of as a spring, wherein the archer pulls back on the bowstring, which contorts the bow such that it has elastic potential energy. When the archer releases the bow, this potential energy becomes the kinetic energy of the arrow. An important fact to realize about archery is this, for consistent shots, an archer has a point near their face, be it their ear, their temple, their cheek, where they always draw he string back to. This means that, barring such things as a decrease in efficiency of the bow over time due to wear and tear, the force the archer exerts on an arrow is the same with every shot. This helps t
The force on a bow is expressed as the draw weight, with units of N, and the draw length is the distance over which the bowstring is pulled
Provided are two graphs which illustrate the relationship between draw weight and the draw length with a recurve bow and a compound bow (the relationship is the same for a recurve bow and a longbow)
The Physics of Archery 2001 The Physics of Archery 2001
With the first graph, you can see that there is a direct relationship between the draw length and the draw weight of a longbow. These two variables (draw length=x, draw weight=F) can be used to find the energy contained in the bow by the equation: Fx/2. The 2 signifies that there are two “arms” of the bow, the top and bottom halves, over which the energy is split.
The second graph is of the compound bow, and you can see that at a certain point, as the draw length increases, the force required to pull the bowstring decreases, forming a parabola.
Using Trigonometry, we can determine what the draw weight of a given bow is, given a few bits of information.
This figure represents the draw length as x, the change in length between the bowstring at rest and the bowstring after being drawn.
The next figure shows the bowstring, the arrow, and the bow as a triangle, with angles A and B, and F representing the spring force of the bow.
Angle B between the arrow and the bowstring, F representing the spring force, and angle A between the spring force F and the bowstring.
Using trigonometry, we can come to the equation:
Again, the 2 represents the presence of two bow arms.
Now, with a means to find the force applied on the arrow, we can use this information to solve more complex problems, like, is there a way to calculate how I should hold my bow to guarantee I hit the target? Well, if I may digress, that answer can be illustrated with a joke I heard, it goes a little something like this.
There's a farmer that raises chickens, and he wants to find out if there is a more efficient way for him do do so, since more efficiency=more money. So, he asks a physicist if he can help him. The physicist says he'll try. He goes off and does some calculations, then comes back to the farmer. The farmer asks, so, can you help me? The physicist says I have good news and bad news. The good news is, yes, I found a way to increase the efficiency of your farming methods. The bad news is, it involves spherical chickens in a vacuum.
All joking aside, the level of physics for which I have been taught just barely scrapes the surface of answering this problem For such calculations, I would undoubtedly have to take such classes that a physics major would take. At this juncture, I can only deal with archery that takes place with no wind resistance.
Within the listed limitations, it is possible to calculate the angle at which a person should hold their bow as long as the following information is available: the weight of the arrow, the distance to the target, the force the bow exerts on the arrow as it leaves the bow ( or the arrows initial speed, whichever works), and the height of the target (in particular, the height of the bullseye above the ground).
We will be using some of the following kinematic equations for projectile motion to solve this problem.
y=yi + Vyit - 1/2gt^2
Vy=Vyi - gt
Vy^2=Vyi^2 - 2g(y-yi)
v^2=Vi^2 + 2ax
With no air resistance, the horizontal velocity, Vx, will be the same throughout the flight of the arrow
To test whether we really can solve such a problem, I shall provide an example myself. Let us say that we have an archer who holds the drawn bow such that the tip of the arrow is 2m above the ground. The distance to the target is 10m. The bullseye of the target is 0.5m above the ground. The arrow weighs 80g. The force the bow exerts on the arrow is 100N. The draw length is .7m. Find the angle necessary to hit the bullseye.
This figure shows the data provided for the example problem.
To solve this problem, first we need to find the initial velocity of the arrow. To do this, we need to use Newton's Second Law, F=ma, to find the acceleration.
By plugging in the mass of the arrow, 80 grams, for m, and the force, 100N, in for F, we can solve for a. We convert grams to the proper units, kilograms.
100N=(80g x 1kg/1000g) a
Now we can use a kinematic equation to solve for v.
Using V^2=Vi^2 + 2ax
v^2=0 + 2(1250m/s^2)(.7m)
So, the initial velocity of the arrow as it leaves the bow is 41.83m/s. But to solve the rest of the problem, we need to do a vector decomposition, to find the vertical and horizontal components of the initial velocity. So, since the horizontal velocity stays the same throughout, we aren't interested in it, what we are interested in is the vertical velocity. If we view the initial velocity, the x part of it, and the y part of it as a right triangl, with the hypotenuse as the initail velocity, then Vyi=Visin(theta). We can then plug Visin(theta) in for Vyi in the kinematic equation Vy^2=Vyi^2 - 2g(y-yi). We get the following:
0= (Visin(theta))^2 - 2(9.8m/s^2)(.5m-2m)
So, using the kinematic equations, we have discovered that the archer should hold the bow up at an angle of 7.45 degrees above the horizontal to hit the bullseye of the target.