Tagged Questions
1
vote
1answer
40 views
Average force and pressure in a 3D box due to quantum non-interacting particles
A gas of non-interacting quantum particles occupies a box with lengths $L_1, L_2, L_3$. Calculate its energy and thus the average force and pressure exerted by the gas on the walls of the box.
I have ...
2
votes
0answers
28 views
error propagation and collision in ideal gas
When dealing with gas, a statistical approach is needed because
For N particles, you have to solve 6N equations which cant be done analytically. To know our time step for numerical solving, you can ...
-1
votes
0answers
25 views
Find the workdone to increase the temperature of an ideal gas by 300c if gas is expanding under [closed]
Find the work done to increase the temperature of an ideal gas by $30^o C$ if gas is expanding under the condition $V \propto \dfrac{t^2}{3}$.
0
votes
2answers
87 views
Air pressure in balloon
I have to calculate the air pressure inside of an hot air balloon. After some searching I found out that I can use the ideal gas law: PV = nRT (from Wikipedia)
So to get the pressure in the balloon I ...
1
vote
1answer
74 views
Volume of gas at which relative fluctuation of gas density occurs
I have the following question:
In what volume of gas occurs 10 % relative fluctuation of gas density
under pressure of $10^5\text{ Pa}$ and temperature of $293.15\text{ K}$?
I don't understand ...
0
votes
1answer
58 views
In $PdV$, what is the value of $P$? $P_1$ or $P_2$?
Say I have an ideal gas that has a known $P_1$, $P_2$, $T_1$, and $T_2$ undergoing a reversible adiabatic process. I want to find the work done so I must use $PV = RT$ to get the change in $V$, so ...
2
votes
1answer
162 views
Canonical partition of a boson gas
I have a 1D gas made of $N$ particles placed in a harmonic potential well, so the Hamiltonian is:
$$ \mathcal H = \sum_{j=1}^N \left ( \frac{p_j^2}{2m} + \frac{1}{2}m\omega^2 x_j^2 \right )$$
The ...
0
votes
1answer
55 views
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 ...
0
votes
0answers
61 views
Using thermodynamics and Kinematics together to solve a parachuter problem?
I need to find a parachutist's displacement after a given height (nearly 37000m) and at a given latitude. I have his mass, area, parachute area, drop height, parachute deployment height, data about ...
1
vote
1answer
72 views
Thermodynamic process when nebula is heated
The basic thermodynamics problem is stated as follows.
The nebula contains a very tenuous gas of a given number density (atoms per volume) that is being heated to a given temperature. What is the ...
2
votes
2answers
891 views
Calculating work done on an ideal gas
I am trying to calculate the work done on an ideal gas in a piston set up where temperature is kept constant. I am given the volume, pressure and temperature.
I know from Boyle's law that volume is ...
1
vote
1answer
404 views
Adiabatic expansion [closed]
I'll start off by saying this is homework, but I ask because I don't understand how the math should work (I don't just want an answer, I'd like an explanation if possible). I understand if this is ...
0
votes
1answer
1k views
Work Done by an Adiabatic Expansion
I am given the information that a parcel of air expands adiabatically (no exchange of heat between parcel and its surroundings) to five times its original volume, and its initial temperature is 20° C. ...
2
votes
1answer
661 views
Work Done in an Isobaric Process
I am given the information that an air parcel undergoes isobaric heating from 0° C to 20° C, and that's all I'm given. I have to determine the work done by the parcel on its surroundings. I know that ...
1
vote
1answer
657 views
Calculate mass of air in a tyre from pressure
How can one calculate the mass of air inside a tyre, given a particular tyre size; a pressure, in $kPa = \frac{1000kg}{m\cdot s^2}$; and assuming room temperature, and normal air composition? I can't ...
-1
votes
1answer
217 views
Black body balloon in vacuum [closed]
The problem statement, all variables and given/known data
There is a perfectly spherical balloon with surface painted black. It is placed in a perfect vacuum. It is gently inflated with an ideal ...
0
votes
1answer
130 views
Expansion of Helmholtz energy
To get an expansion of Helmholtz energy of
a) an ideal gas
b) a Van der waals gas
we must integrate
$\left ( \frac{\delta A }{\delta V} \right )_{T}=-P$
I saw the solution is :
Can you ...
