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Laws of motion

## Intro

Sir Issac Newton's Three Laws of Motion and his Law of Gravity govern the ways we can increase the power of our martial arts techniques.

## Definitions

• Matter. A physical substance that occupies space and possesses mass.
• Object. Something composed of matter.
• Mass. Mass is how much matter is in an object. For practical purposes, it is an object’s weight. As it pertains to the martial arts, it’s your weight or your opponent’s weight.
• Force. Force is a push or a pull that can act upon an object. As it pertains to the martial arts, your either push on your opponent or parts thereof, which includes striking or you can pull on your opponent or parts thereof or you can push and pull on your opponent or parts thereof
• Speed. This is the rate an object moves; the distance it moves per unit of time. Example, the speed of a punch can be up to 43 miles per hour.
• Velocity. This is the speed of an object in a given direction. For example, 100 miles per hour due north. Example, the velocity of the punch from his hip to the opponent’s nose was 25 miles per hour.
• Acceleration. This is how fast the velocity is changing. Example, the acceleration of his punch was 5 meters per second per second.

## First Law

Newton's First Law of Motion says that an object in motion will remain in motion unless acted upon by some force and that an object with no motion (at rest) will remain at rest until acted upon by some force. The punching arm will remain at rest and not execute a punch until acted upon by your muscles. Once the punch is in motion, it will remain in motion until acted upon by another force, such as a face or a block.

## Second Law

Newton's Second Law of Motion says that force an object exerts is equal to the mass of the object times its acceleration (F=MA). It essentially says that forces are necessary to accelerate objects with mass, and it defines how big that force will be for the particular object.

If the acceleration of the punches of two people is kept constant, a punch from the heavier person will hit with more force. A ten-pound weight dropped on your foot will hurt more than a 5-pound weight dropped on your foot.

If the mass of two people is the same, the punch from the person with the fastest punch will hit with more force. To illustrate this, throw a rubber band as hard as you can at a friend's arm. Ask the friend if it hurt? Now hook the rubber band over a finger, pull it back, and shoot it at the friend's arm. No need to ask this time; the friend will probably let you know that it hurt. Speed hurts!

## Third Law

Newton's Third Law of Motion says that for every force acting on an object by another object there is an equal and opposite force that acts upon the first object by the second one. When you punch a brick wall with a certain amount of force, the wall will exert the same amount of force on your fist. Since the wall is solid and immovable, your force will not do it any damage; the same cannot be said for your fist.

## Law of Gravity

Newton's Law of Gravity says that gravity is a force that acts between any two objects with mass, and that force increases if the mass increases and decreases if the distance between the two objects increases. This force is always attractive, that is, it always works to pull the objects closer together. Maybe this why skinny people are attracted to fat people.

Gravity is not a source of energy, but it does allow an object raised above the ground to possess kinetic energy, so the higher you raise your arm before breaking a horizontal board with a vertical punch, the more power will be in the punch. Likewise, jumping before the punch will generate more kinetic energy in the punch.

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