# Newton's Laws of Motion

### Keywords

acceleration, inertia, electric charge, pure charge theory
Newtons three laws of motion are.

1. Every body will remain at rest, or in a uniform state of motion unless acted upon by a force.
2. When a force acts upon a body, it imparts an acceleration proportional to the force and inversely proportional to the mass of the body and in the direction of the force.
3. Every action has an equal and opposite reaction.

The exact meaning of the word action is not known, we generally take it to mean a force or an exchange of momentum.

The pure charge theory states that any change in the state of motion of an electric charge will generate a force opposing that change in motion. This force is proportional to the acceleration and to the energy content of the electric field of the charge. This translates into Newton's first and second laws. The charge cannot move off from rest or change its velocity out of some whim of its own, because a force would immediately arise opposing the change. Only if we exert a force on the charge will we produce an acceleration and that acceleration will be such as to generate a force equal and opposite to the force which caused the acceleration.

In Newtonian mechanics, we call any object we want to deal with a body, be it an electron or a planet. The pure charge theory demonstrates that a single charge will obey Newtons laws of motion. Kilogram weights, railway engines and planets are composed of real matter made up of three types of charged particles called electrons, up quarks and down quarks. If we model these with pure charges, we can construct a model of a lump of real matter. We find that the motion of individual charges is very complex, but we can consider the motion of a charge within a body to be due to internal motion within its atom plus thermal motion of its atom plus the motion of the body. We can then examine the kinetic energy of a charge in terms of these components of its motion. This is dominated by the velocity of the charge within its atom and fluctuates wildly as the charges interact. If we sum over all the charges in a single atom, we can identify a set of terms which represent the kinetic energy of the atom and a set of terms which give the internal energy of the atom. We can now consider a group of atoms which comprise a body, in the Newtonian mechanics sense of the word, and do the same thing again. We can now identify a set of terms which gives the kinetic energy of the body, a set of terms which give the thermal energy of the body and a set of terms giving the internal kinetic energy of the atoms.

The fact that we can correctly identify a set of terms which contain the kinetic energy of a body composed of atoms, which in tern are composed of charged particles, means that changes in the state of motion of the body will require the action of forces which impart to, or adsorb from, the corresponding change in kinetic energy of the body. Thus the body as such obeys Newton's of motion because each one of its component charges obeys them. We can never do the actual arithmetic because a kilogram mass contains about 1027 individual charges and we would need to look at their motion about 1017 times every second. Fortunately this kind of problem was tackled some time ago in the branch of physics called statistical thermodynamics.