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 Do rockets work in space ? (16)

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rocketsneeda(21) pic



Do rockets work in space ?

I wish to debate the topic of the use of Newtons Laws to prove why a rocket can function in space vacuum.
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F=ma does not prove a force exists…..

As there are systems that are nearly isolated …ie a rocket approaching space…

A system in isolation cannot claim velocity by its own force.

F=ma was proposed in 1716 in a book by Jacob Hermann (1678-1733, Mathematician). Newton’s Principia (1st edition 1686, 2nd edition 1713, and 3rd edition 1726) does not contain this formula.

: If there were no gravity, and if the air did not impede the motion of bodies, then any body will continue its given motion with uniform velocity in a straight line.

: Every body under the sole action of its innate force moves uniformly in a straight line indefinitely unless something extraneous hinders it.

: Every body perseveres in its state of being at rest or of moving uniformly straight forward except insofar as it is compelled to change its state by forces impressed.

What is an impressed force....This force consists in the action only, and remains no longer in the body when the action is over. For a body maintains every new state it acquires by its inertia only. But impressed forces are of different origins, as from percussion, from pressure, from centripetal force.

'Equal and opposite'

One problem frequently observed by physics educators is that students tend to apply Newton's Third Law to pairs of 'equal and opposite' forces acting on the same object.

What is an explosion….

Explosion is a rapid expansion process or explosive expansion…

What is Rapid expansion…

Pressure..

What is pressure….

Containment of gas impeding the expansion of molecules.

What is containment….

An inhabiting medium or a sealed container ie JAR with lid shut tight or an Atmosphere kept at homeostasis. The latter is a miracle in itself and there seems to be no other like it..and jars are special too.

What would an explosive expansion behave like in space….

Lets initiate a rapid chemical expansion that has its own source of oxygen…but first we have to talk about plasmodic decarboxultion.

Fire or the carbon fueled plasma reaction is an electrical phenomena….Degree of ionization. For plasma to exist, ionization is necessary. ... Even a partially ionized gas in which as little as 1% of the particles are ionized can have the characteristics of a plasma (i.e., response to magnetic fields and high electrical conductivity).

SO can a fire burn in space even with a oxygen source?

Now back to the issue of pressure in a vacuum…

OK say we can make something burn and rapidly expand in space, what is it expanding against ? lets talk rocket chamber..

Deep on the recesses of a rocket motor there is a environment that is close to be a JAR with the lid on…can this place produce rapid exapnsion yes in theory if CHOKED FLOW conditions are sustained..

Awesome we have a pressure vessel that can contain SAY 1000psi..so this pressure vessel gas is static pressure with sub sonic velocity, which moves through the nozzle throat and gains a little velocity and pressure SAY 1001psi … So this gas now passes out of the nozzle throat into the divergent section and rapidly expands moving at super sonic veolcity…STOP this sounds like its great everything we need, Reaction, Containment, Acceleration and now lastly the most important factor FORCE..

Re-cap, sub sonic flow in the chamber of a static nature balanced and at pressure, SCIENCE determines erroneously that internally this chamber is receiving the bulk of the effort or kinetic energy being displaced against the opposite wall to the outlet.. BUT as ive explained in simple terms and it is verified in rocket theorem chamber gas velocity is static sub sonic velocity, and this static nature of the chamber certainly does not move the rocket, it is also evident that Divergent Nozzle surface area is quite large compared to chamber surface area and is where most 98percent of the kinetic energy is displaced externally to the reaction chamber and against the bulk of the surface area of the rocket motor..

OK so lets look at the supersonic velocity end of the motor where rapid expansion is taking place and we might even find a force for thrust..

Super sonic gas(funny how its measured against the threshold of the speed of sound, don't you think) Rapidly expanding against ?

This is where is gets sad for an astronaut, for example what if an astronaut wanted to go and swim in space, don't be silly there's no Air, Water, Buoyancy or any medium a thing can push itself off.. Where does this leave Rapidly expanding Chemical plasmodic reaction, unfortunately without force which is experimentally verified by JOULES EXPANSION..

Could it be that im a correct to say that an explosion in space is going to be a very anticlimactic flash without external compression with no impedance without force applied as the gas will not interact with itself or the environment or it origins of containment..

Amarel(5669) Clarified
1 point

Could it be that im a correct to say that an explosion in space is going to be a very anticlimactic flash without external compression with no impedance without force applied as the gas will not interact with itself or the environment or it origins of containment

Why would an explosion not interact with its origin of containment?

rocketsneeda(21) Clarified
1 point

The reaction has no impedance, or anything to contain and press upon it..

Joules Expansion experimentally verifies that gas released into a vacuum will not yield any force as the expansion is unhindered..It is determined that gas undergoes elastic collisions which transfer no energy to their surrounding or each other when freely expanding...Hence why a compressed gas maintains its pressure in containment and looses no energy so long as temp and containment are homogeneous.

If you open a soda bottle on earth it will slowly fizz and bubble if you do it space it will rapidly equalize in pressure but do so with no work applied, as the work of expansion is already done by the vacuum...

BigOats(1449) Disputed
1 point

The formula here isn't F=ma, it's F=dp/dt.

Where p is the total momentum of the rocket and the fuel.

Let's say the rocket is moving vertically upward in Earth's gravity field.

So we can use scalars instead of vectors.

The rocket velocity V is directed vertically.

So we have F = dP/dt;

If the rocket mass is M(t), the momentum is M(t)v(t)

If the engine generates a stream with a mass flux Q, then

dM/dt = Q.

The engine stream velocity is

V1xDxS = Q, where S is the nuzzle area and D is the fuel density.

Toal momentum of fuel emitted ofer time T is

P(t) = QxV1XT = DxSxV1^2*T

So the momentum flux is W = DxSxV1^2 = const.

Let P1 be the rocket's momentum and P2 the emitted fuel total momentum, so P = P1 + P2

We have

dP/dt = dP1/dt + dP2/dt = F;

dP2/dt is exactly the momentum flux due to duel emittion, so dP2/dt = W;

So, we have

dP1/dt + W = F;

dP1/dt = F - W;

Now, P1 = MV, where V is the rocket's velocity.

So:

d(MV)/dt = VxdM/dt + MxdV/dt = F - W;

We have dM/dt = Q, so

MxdV/dt + QxV = F - W;

The gravity force F = MxM1xG/r^2;

So we have MxdV/dt + QxV = MxM1xG/r^2 - W;

Using ' as notation for first derivative over time, and '' for second derivative, we have:

V:=r(t)';

dV/dt =r(t)''

So, finally:

Mr(t)'' + Qr'(t) = MxM1xG/r^2 - W.

And that is the differential equation for rocket propelled motion in Earth gravity.

rocketsneeda(21) Disputed
1 point

BigOats, math is a good tool its function is to predict and calculate variables in models. So the achilles heel of maths is the model you are using yes some are GOOD ENOUGH but are still incorrect due to simple reason of definitions of our universe which are based on models, so you can now understand the issue with maths and its presumptions aligned with preconceived outcomes determined by the model..

So put your calculator down and realize this fundamental error in the above equation MOMENTUM FLUX due to emission..This is assumed and not even explained as if it is an empirical definition like F=ma which is not empirical and cannot be proven correct or false it is unfalsifiable. Occurrences are not causes.. Where do you cite anywhere in the rocket equation the effect of Joules Expansion and shockwave interaction with an external medium AIR...

I dispute the relevance of any rocket equation as none use vacuum principles or shock-waves created from displacement of fast hot gas meeting slow cool gas as components of force and lack off force once craft reach near vacuum of space...

So do please show me your revised equation when it includes the above missing components Joules Expansion and Bernoullis principles explaining shockwaves.. Otherwise your math is just a shopfront without merchandise in the rear.

1 point

I'm going to admit up front I don't know the science. This isn't my field.

But what I do think I know is past space ships have indeed had rockets used to help steer, whether it was to adjust orbit or flight path, which means even if they didn't work for increasing thrust and speed they do work in some limited capacity.

rocketsneeda(21) Disputed
1 point

Hi, ill be upfront im not much of a debater, so my delivery and info may staggered....

Rockets rely upon an internal chemical reaction.

Fire is the rapid oxidation of a material in the exothermic chemical process of combustion, releasing heat, light, and various reaction products.

Fire is an oxidizing chemical reaction that releases heat and light. The actual flames that you see moving and glowing when something is burning are simply gas that is still reacting and giving off light. Plasma are gases in which a good fraction of the molecules are ionized.

Ionization is the process by which an atom or a molecule acquires a negative or positive charge by gaining or losing electrons to form ions, often in conjunction with other chemical changes.

A rocket has the adequate components to create a chemical reaction, BUT fire is a plasma which is an electrical phenomena.

Vacuum is a poor conductor in fact it is a very poor conductor, if i could create a bubble of atmosphere in space and start a fire in it, it wouldn't burn as there is no earth or positive dynamic to conduct the plasmodic reaction that creates fire...

Grenache(6053) Clarified
1 point

All that makes a lot of sense, and I'm not disputing you, but then why do thruster rockets work to change courses?

yes, conservation of energy should be an explanation.........