Thursday, April 11, 2013

Physics and Martial Arts, Part I: Of Staves and Gravity


a : a long stick carried in the hand for support in walking
b : a supporting rod: as (1) archaic : shaft 1a(1) (2) : a crosspiece in a ladder or chair : rung (3) : flagstaff (4) : a pivoted arbor
c : clubcudgel

I have recently begun a love affair with the staff as a weapon.  Perhaps the simplest martial arts weapon, and perhaps the simplest weapon of all, a staff is merely a rod.  By sheer definition, it is nothing more, and nothing less.  Yet, despite its simplicity, I argue that the staff is truly a thing of beauty; a wonder of a weapon, and, in the right hands, a thing to shock and awe.  What makes the staff such a beautiful weapon?  Physics.  Simple physics. 
We begin with the staff's construction.  Most staves used in martial arts are constructed of wood.  Red oak is common, or rattan, for a lighter-weight staff; but whatever a staff happens to be composed of, it is invariably a hard material, light enough to wield, but solid enough to make an impact.
It is here, in examining the construction of the staff, that we discover the key to its beauty: mass.  A staff, be it made of wood, metal, or plastic, has mass.  It has substance.  It is there.
There are two reasons why mass is important.  The less-important one is this: in order to be effective as a weapon, a staff must have appropriate mass.  It need not be excessively massive; a staff constructed of osmium, or iron, would be incredibly difficult to wield.  However, it must have sufficient mass.  A staff constructed of glass, or hard candy, for example, would be very little use as a weapon.
Mass is important because it gives the staff substance, and makes it effective as a striking weapon; but mass is significant for a far greater reason.  Physics dictates that, when an object has mass, it is affected by gravity.  Gravity is a force that causes an object with mass to be attracted to any other object with mass.  Here, on planet Earth, all objects are attracted to the Earth, the most massive thing in our immediate environment.  This is "weight."  Every object is attracted to the center of the Earth, in varying degrees, depending upon how great its mass is.  Regardless of weight, however, all objects fall at the same rate.

A staff, then, like any other object, must have weight.  Like any other object, the staff's weight is concentrated in its "center of gravity."  Everyone, and everything, has a center of gravity.  Depending on the object's shape, its center of gravity may be difficult to find; but an object's center of gravity is the point around which the object, if thrown, rotates.  It is the point where an object can be balanced, even upon a very sharp point, as long as the point is placed directly under.

This brings us back to the staff.  A staff, by definition, is a simple rod.  It is, in essence, a three-dimensional line.  Thus, a staff, as long as it is straight and true, must have its center of gravity directly in its middle.  There, in its exact middle, lies the point around which it rotates, and there lies the point where it may be balanced.

Ok.  A staff has mass, so it has weight.  It has weight, so it rotates around its center of gravity.  Its center of gravity has to be in its middle.  So what?

So, this brings us to torque, both the key, and the "ki," (ha!) to the staff's power.  Stay tuned...

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