The kinetic-theory tag has no wiki summary.
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How does the volume change affect an adiabatic process?
A gas consisting of rigid diatomic molecules was initially under standard conditions. Then the gas was compressed adiabatically, 5 times the original volume. Find the mean KE of rotating molecules ...
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Probability Density Function for Dust in the Colision-less Vlasov equation
My problem is the following: I'm trying to model a dust (pressure-less relativistic gas) in the presence of electromagnetic field using colisioness vlasov-equation (relativistic version of boltzmann ...
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Momentum change in colisions (Drude Model)
A particle suffers elastic colisions with scattering centers with a probability of colision per unit time $\lambda$. After a colision the particle is in a direction caracterized by a solid angle ...
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Height of a piston in a heated cylinder containing H2O
I'm a first time user and I hope I won't be too enigmatic asking the following question:
I have a cylinder (radius= $6$ $\text{cm}$) with a frictionless piston on top of it and inside $30$ $g$ of ...
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1answer
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Root Mean Square Speed of Gas
The RMS speed of particles in a gas is
$v_{rms} = \sqrt{\frac{3RT}{M}}$
where $M$ = molar mass; according to this Wiki entry: http://en.wikipedia.org/wiki/Root-mean-square_speed
The gas laws ...
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249 views
formula for mean free path in two dimensions
I'm running some simulations of particle collisions in two dimensions with discretised time and space. In essence, particles only collide if they occupy the same location (cell) at the same time step. ...
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Working out the mean velocity of particles in a gas
I'm trying to answer the following question:
Air consists of molecules Oxygen (Molecular mass = 32$amu$) and Nitrogen (Molecular mass = 28$amu$). Calculate the two mean translational kinetic ...
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215 views
Angular Momentum of Diatomic Molecules
I have run into a problem trying to calculate angular momenta and I wonder if someone can set me straight.
I think I know that the lowest order rotational mode should have angular momentum of h, and ...
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Confined in a box, what is the average distance between a particle hitting a side?
This particle, alone in the box, at a constant velocity $v$, travels in straight lines until hitting a side of the hollow cube, bouncing off in a random direction independent of incident angle (I know ...
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Influence of choice of statistics on gas kinetics
In the derivation of distributions over energy states, a common assumption made is that under normal conditions (normal from a fluid dynamics standpoint, so > 300K typically) the energy states are ...
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Does the kinetic theory of gases means gases mix almost instantaneously?
This theory has bugged me ever since my first physics class on the subject. If this (http://en.wikipedia.org/wiki/Kinetic_theory) is true, it leads me to a few weird conclusions.
Opening the rear ...
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How to deduce E=(3/2)kT?
It says in my course notes that a particle has so-called "kinetic energy"
$E=\frac{3}{2}kT=\frac{1}{2}mv^²$
Where does this formula come from? What is k?
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Validity of the Multi-Species Navier-Stokes Equations for real gases
I'm wondering what are the validity limits of Multi-Species Navier-Stokes equations. I'm aware of the limit for rarefied gases. But is there any new limit that arises in the context of real gases?
I ...
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1answer
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On non-local physics
Recently I've encountered work by prof. B.V Alekseev, in which he claims that some physical problems can be easily solved if we consider non-local interactions in kinetic theory (interactions of ...
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1answer
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Why is the $\langle v_{x}^{2} \rangle=\frac{1}{3} \langle v^2 \rangle$?
For a randomly moving particle. Or, I suppose that 1/3 could generalise to 1/n, where n is the non rotational degrees of freedom for that particle.
Related reference Kinetic Theory of Gasses.
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Pressure change due to fan removing air from a non-airtight room
The following problem occurred to me today:
Suppose a $100\mathrm{cfm}$ fan is pushing air out of a large room which is airtight except for a $10 \mathrm{cm}^2$ hole. The air pressure outside the ...
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171 views
Difference in vertical stratification of partial pressure due to gravity
Say you have a mixture of two ideal gases in the presence of gravity. There is a vertical pressure gradient on the mixture due to the force balance. This condition is required to prevent the entire ...
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Simple: What do these ballistic impact numbers represent?
I bought physics for game programmers, found here, today to study ballistic impact, but I'm confused as to where a few numbers are coming from. I'm basically looking to understand what the values ...
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2answers
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What physical processes may underly the collisional term in the Boltzmann equation, and how do they increase entropy?
Consider particles interacting only by long-range (inverse square law) forces, either attractive or repulsive. I am comfortable with the idea that their behavior may be described by the collsionless ...
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1answer
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What conditions must be met for a ball to roll perfectly down an incline without slipping?
What conditions must be met for a ball to roll perfectly down an incline without slipping? A mathematically rigorous definition, please.
I honestly don't know where to begin with answering this ...
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1answer
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Collision frequency at surfaces
Collision frequency for particles in gases is well known, and collision theory is used to derive chemical reaction rates in gases, (and particles in liquid solutions as well). Using the mean velocity ...
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How does evaporation affect the temperature of the air?
A wet object or a volume of water will decrease in temperature due to the effect of evaporation. We understand this to be because of the molecular kinetics, where the faster water molecules escape ...
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Understanding Heat
Heat or thermal energy as understood is nothing but motion of molecules of the matter. If the molecules are tightly bound (in case of solids), it is to-and-fro molecular vibrations, otherwise it is ...
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Why is a hot air balloon “stiff”?
1) Why is a hot air balloon stiff?
2) Is the pressure inside the balloon higher than the pressure outside (atmospheric pressure)?
3) If the pressure inside is higher than the outside, how is it ...
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Accuracy of the Boltzmann equation
I have had this question for some time now. Hopefully someone can answer it.
I know that the Boltzmann equation is widely regarded as a cornerstone of statistical mechanics and many applications have ...
