The Physics of Archery
There are not many activities out there that relax and soothe me quite like shooting my bow. It is not as simple as it sounds though, just pulling on the string, releasing the string, and watching the arrow fly towards your target. There are a number of aspects that must be taken into consideration when trying to shoot a bow and arrow efficiently, this is where we will get into the physics of archery.
There are two main things to consider when looking at archery and the physics concepts behind it. First there is the bow, which basically is a device that uses human force over a distance and converts that into stored Mechanical Potential Energy. The second factor involves that stored Mechanical Energy being converted once again into Kinetic Energy when the string is released, almost all of that Kinetic Energy is transferred into the released arrow. Another way to look at a bow is in respect to a spring, a bow is almost like a spring that is storing energy that is to be transferred into the arrow once the string is released.
To realize the amount of force that is applied from the bow we must look at a number of ideas and concepts. For this application we will use only a Recurve bow or a Reflex bow, which basically is a long piece of wood with a rigid handle and two flexible limbs that are “recurved” away from the archer. Then those limbs are simply pulled back towards the archer by the means of a string or number of strings. There are also a number of other bow concepts we could look at, for instance the compound bow or even the crossbow. The compound bow is similar in design except that it uses cams, pulleys, and mechanical levers to produce a greater amount of stored energy with a less amount of human force required. The crossbow is also very similar to the Recurve bow with the difference being that the Bow or commonly called the “Prod” is connected horizontally to a piece of wood or fiberglass which is called the “Tiller.” Also in a crossbow a mechanical release attached to the bow is used so that a greater amount of energy can be maintained without physically holding the string back.
The materials that construct the Recurve bow must be taken into consideration when looking at the force applied from the bow. The most popular material for traditional archers today would have to be a certain type of wood from the yew tree. The reason for this particular choice of wood is that it contains the highest elastic energy storage per unit mass for any type of wood, which is around 700 Jkg-1. Which is very close to having the same rating as spring steel. However with technology these days more people are leaning towards a type of carbon-fiberglass laminate. This particular combination brings both a lighter weight than wood and a higher elasticity rating. The reason some wood bows are still around is due to the fact the old timer-traditional type archers shun using any kind of technology or advancements to aid them in...