Have you ever watched archers shoot in the Olympics and wondered why they swing their bows? It seems like an odd thing to do – but, archers swing their bows because it helps them achieve a better shot.
The physics of archery can help us understand why this is the case. When an archer draws their bow, they are storing energy in the form of tension in the low limbs and string. This tension is released when they let go of the string and it propels the arrow forward. When the string is released and the arms of the arrow snap forward, the force propels the entire bow forward, out of the archer’s hand. It’s similar to the when you hold an elastic band in one hand and stretch it back with the other. When you release it, the band will either fly forward, or hit the back of your hand.
So, why don’t they just grip the bow to prevent it from coming out of their hand?
If the archer maintains a tight grip on the bow, the grip can cause the bow to slightly twist or shift. Since Olympic archers are shooting at a target 70 meters away, a small twitch or shift in hand position can make a significant difference in where the arrow lands. To prevent this grip from interfering with the bow, the archer must keep a very light grip, or no grip on the bow. The hand is more cupping or supporting the bow than grasping it. The bow is actually being pressed against the outstretched bow hand by the backwards force of the hand pulling back on the string.
When the string is released, and launches the arrow, the forward force of the string and the limbs (or arms) of the bow send the entire bow forward. As the bow jumps forward and out of the archer’s hand, it is caught by a string (finger sling) that is tied around the thumb and forefinger. This finger sling, which can be a simple shoelace, acts like a seatbelt for the bow, which is caught mid-air by the string, then tilts forward. The forward swing or tilt is due to how the long stabilizer on the front of the bow makes it front heavy. The archer allows it to fall as part of his follow through, keeping a steady form as the arrow leaves the bow and flies toward the target.
I have personally forgotten to attach my finger sling and witnessed the “physics” of the bow flying forward away from my and crashing to the ground. With a finger sling, you can allow the bow to do its job without gripping it, and allow the sling to catch the bow, giving you that cool looking bow swing!
So next time you see an archer swinging their bow after taking a shot, remember that there’s a good reason for it – they’re trying to get the best shot possible!
Do you have any questions about the physics of archery? Let us know in the comments below!