Tuesday, March 31, 2015

The Relationship of Physics to Karate

Guest Editor - Raphael Gutierrez, MD

Many people argue about the best way to get power into a punch, but they fail to use any rational thought, relying instead on their dogmatic beliefs.  If you are an acolyte of these peoples thinking then just enjoy your Kool-aid -- but don't try to pass it off as "scientific"  because you'll be called on it.

To understand the hoM2V2w to get power from any punch you may have to look at high-school levels of collision physics because without it your explanation is merely pseudo-science and no more than that.

The first thing that has to be understood is the conservation of momentum which means that the mass times velocity of one body is equal to the mass times velocity of another or in equation format:  M1V1=M2V2

This equation does not look at the loss of energy to entropy measured via heat and sound can be neglected in our circumstances.

No, we must ze that there two types of collisions - an elastic one where the force is lessened due  to deformations caused by the impact or ineleastic  where no deformation occurs.  In layman's terms, a perfect elastic  collision would be like a punch that breaks something but does not lead to much movement.

What will cause the damage is the transfer of Kinetic Energy (KE) MV^MV^of the punch and how fast that energy is transferred.  As Kinetic Energy is defineD by:  KE=1/2MV * 2.

Let/s say we have  three very different objects of energy.  Let's take a Smart Car with 1,000kg, a human weighing 165 lbs. and a baseball with a mass of 1.45kg.  If all three are  moving at the same speed, the car would have more KE but what if all three  had .the same KE? 

Calculating that a ball moving 40m/s (about 90 mph) and will have KE of 116.  For a 1,000kg car to have the same KE it would have to be moving at 0.48 m/s or one mph.  The human would be moving at 1.76m/or 4 mph.

What would cause more damage to you?  A Smart Car going 1 mph, being bumped into by an average-sized man or a fastball from someone like Nolan Ryan?  Unless you are glued to the ground, a fastball would do more damage.  The reason has to do with how fast the force is transferred, the faster it is, the more  deformity will be seen due to the initial transfer of energy or the impulse.

It all has to do with the speed at which the energy is transferred. f

(Editor's note to guest editor.  RHG - never again!  My brain is knotted just typing this.  It could have been Urdu for all I know.)


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