Momentum and Kinetic Energy
By: Thomas Lee Abshier, ND
Momentum and kinetic energy are both based upon the electromagnetic field associated
with particles in a moving mass. Energy and momentum are conserved in all elastic
interactions; that is, in cases where kinetic energy is not converted to other forms
of energy such as heat, light, sound, or potential energy (gravitational, electrical
or magnetic). In inelastic collisions, momentum is conserved, and the total energy
is conserved. But, in inelastic collisions, the kinetic energy is converted into
other forms of energy, and thus is not available for passing into the target.
The question under consideration is why momentum is conserved, and kinetic energy
is not? The answer seems to lie in the fact that momentum is a vector quantity,
and the vector component of momentum is conserved.
Momentum:
p =mv
p = momentum of the mass at a particular velocity
m = mass having a particular
velocity
v = velocity of the mass
http://en.wikipedia.org/wiki/Momentum
Impulse:
I = F t = m v = p
I = Impulse, Definition: Impulse = the application of force
for a period of time.
F = Force applied (note: equation is only applicable for constant
force)
m = mass to which the force is applied
t = time interval over which force is
applied
v = change in velocity due to the applied force
p = change in momentum due
to change in velocity
http://en.wikipedia.org/wiki/Impulse
Force:
F= ma = m dv/dt = m d²x/d²t = dp/dt
These concepts of kinetic energy and momentum have been raised to the level of primary
phenomena by conventional physical theory. But, in fact Force is the underlying
agent that produces action and the entire range of manifest phenomena. Kinetic energy
and momentum are secondary aggregate phenomena that allow us to engineer and predict
based upon these macro concepts.
With the goal of proving this thesis, let us examine the various physical processes
involved in rocket propulsion so as to illustrate the connection between Momentum,
Kinetic Energy, and Force. When rocket fuel is burned, it builds up a high pressure
inside a combustion chamber. The high thermal energy of the combustion products
is allowed to escape through a nozzle, which directs the molecules of escaping gas
in a single direction, thus minimizing back pressure and maximizing their velocity.
The conservation of momentum declares that the momentum backwards equals the momentum
forwards, so as to at each moment create a net zero velocity for the center of mass.
Conservation of momentum dictates that the rocket will be thrust forward because
of the backwards thrust of the high velocity exhaust products. The forward thrust
of the rocket will occur even in space where there is no stable platform against
which to push.
But, the concept that the rocket moves forward because of conservation of momentum
is a high level explanation, not addressing the real reason why the rocket ship moves
forward. Conservation of momentum is a useful engineering concept, not a reason
why the rocket is thrust forward in response to the combustion products’ backward
thrust.
The actual reason for the backwards thrust of the combustion products, and forward
thrust of the rocket is the application of Force particles in the forward direction
and backward direction. The generation of force proceeded as follows:
1) Two components of the propellant molecule were bound together with a high-energy
bond. This bond was broken by first raising the molecular internal energy to its
activated energy, which is the place where the repulsion of the outer shells of two
bonded atoms is equal to attraction provided by the shared electron. Just beyond
this critical separation distance, the repulsion between atoms dominates and the
two molecular pieces separate, propelled by this repulsion. The net kinetic energy
released in this repulsive acceleration is greater than the energy used to bring
the propellant to the activation energy. Thus, a net release of energy follows the
propellant combustion corresponding to the different of activation energy and kinetic
energy released. That energy was stored in the chemical bonds at the time of the
propellant’s manufacture.
2) The Kinetic Energy of propellant combustion is randomly oriented, thus it is measured
in terms of Thermal Energy. But, thermal energy is simply a term used to statistically
characterize the average kinetic energy of a large number of randomly moving particles.
This thermal energy can be focused into a single direction via a nozzle, and produce
a mechanical thrust.
3) The energy stored in the chemical bonds is stored by supplying sufficient force
to move atoms against the repulsion of the outer shells. The amount of energy required
to initiate the formation of a chemical bond is:
activation energy = work = force x distance
Once the activation energy is reached, then the atoms have overcome their repulsion,
and are drawn toward each other by the attraction associated with sharing electrons.
In this phase the new molecule releases energy. The kinetic energy that was applied
to the two atoms to produce sufficient proximity so as to be able to bind by sharing
electrons is the energy of activation for the chemical bond. After the atoms are
at the place of activation, they are drawn together, accelerate to a velocity, compress
bonds, release the compression, expand to the outer limits of the bond, and are pulled
back inward. Thus, an oscillatory vibration of the molecule holds the energy of
bonding for a time. , which in turn causes collisions and transfer of energy to
other
To store energy in a highly exothermic bond, such as a rocket propellant, the energy
could be supplied to the reactants by placing them in a high temperature and/or high-pressure
gas or solution. These high energy conditions supply the needed activation energy
to create the endothermic reaction. An endothermic reaction requires energy to push
it forward to the point where the atoms formed a bond. Once formed and stable inside
the energy well of their bond, they remain in that configuration until the activation
energy of a spark or concussion initiates the high-energy exothermic dissociation
reaction.
4) As the atoms dissociate with high energy and velocity, they create a high temperature
and high pressure combustion chamber environment. The gasses expand and push out
of the nozzle in one direction. Thus, there is pressure equally distributed throughout
the combustion chamber pressing equally on all of its inner surfaces, except the
nozzle orifice. The forces on the rocket are thus imbalanced causing the rocket
body accelerate in the direction opposite to its nozzle. The combustion chamber
pressure pushes forward on the rocket body, and because of the deficient corresponding
pressure pushing backward on the nozzle orifice a net forward thrust results.
The more perfect the Venturi tube slope of the inlet to throat, and throat to outlet
the less the backpressure in the area of the nozzle orifice. The inward and outward
slope of the venturi tube is engineered so as to produce a flow of particles which
direct the escaping particles in an axial direction rather than perpendicular to
the rocket path. This corresponds to a minimization of backpressure, which has a
corollary effect of maximizing the flow rate of mass through the orifice, which in
turn maximizes momentum. In summary, an imbalance of forces causes the acceleration
of the rocket.
Engineers (rocket scientists) use the concept of conservation of Momentum to calculate
the force, and thus the force on the rocket during engine burn. But, we can see
from the above analysis that Momentum is not a primary, first principle, or elemental
concept. Rather, Momentum is a second order concept which follows from the primary
principles of Force. Such concepts as momentum are useful for macro analysis of
complex systems of particles to engineer systems to calculate the expected effect,
but they do not indicate the existence or primacy of another physical principle on
the elemental level.
