# Tagged Questions

Applies to questions of primarily educational value - not only questions that arise from actual homework assignments, but any question where it is preferable to guide the asker to the answer rather than giving it away outright. Please READ THE GUIDANCE IN META before asking homework questions.

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### Density of states of a photon gas in volume V and temperature T

I have a question on the density of states for a photon gas: Suppose I have a photon gas in a box of volume $V$ at temperature $T$. If I enumerate the total number of states accessible to the system ...
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### What is the optimal weight ratio of a two-stage rocket?

I've been researching this for some time now and I got stuck. The best resource I've found is this book. The "optimising a multistage rocket" part talks about a three stage rocket but it seems ...
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### stable equilibrium in the system

I'm trying to understand the solution of the following problem. A solid cube of uniform density and sides of b is in equilibrium on top of a cylinder of radius R. The planes of four sides of the ...
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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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### Question regarding operators and cylindrical coordinates

I have the following problem in my hand: I need to arrive from the Cartesian expression $$x_{j}{\partial_{k}}x_{j}{\partial_{k}}-x_{j}{\partial_{k}}x_{k}{\partial_{j}}$$ to this expression: ...
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### Relativistic canonical transformation

What is relativistic canonical transformation? I need every piece of information about it. Does anyone know a reference or an article about relativistic canonical transformation? For example, in ...
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### Object on an inclined plane

I was solving a question about inclined planes, and it got me thinking: Imagine a scenario where, an object is on an inclined plane and the inclined plane is on a frictionless surface, and is itself ...
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### Minimum thickness of bubble ensuring max reflectance

A soap bubble has index of refraction of 1.33. What minimum thickness of this bubble will ensure max reflectance of normally incident 530 nm light? Ans is 99.6, but how do I get that? I am ...
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### Determining the length of a Torsional Pendulum

Currently working on this question, however I'm not sure how to solve it. As a pendulum swings in simple harmonic motion at the surface of the Earth, the angle the pendulum makes relative to its ...
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### What does this notation mean in terms of quantic numbers, and how to imagine the electrons in this quantic system? (Helium $2^1$ $P$ and $2^3$ $P$)

Helium atom in the $2^1$ $P$ and $2^3$ $P$ excited states Now I'm guessing that 1 electron should be considered in the 1s state, but what about the other? Should I consider the other as simply ...
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### Can a magnet spin a small machine?

If you were to build an upright machine that had a rod fitted into a ball bearing at the base and was secured to another rod at the top of the initial rod extending perpendicularly. To which you ...
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### Is it possible to manipulate only one pole of a magnetic field, using a bar magnet?

The magnetic field of a bar magnet shows that the N pole field is repelling outward from the tip, is it possible to redirect the field of corners of the magnet so the field is also repelling outward? ...
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### Equilibrium of a sphere in a water tank

A rigid sphere of radius $R_S$ made from a material with specific gravity $SG_s$ is completely submerged in a tank of water with radius $R_t$ and initial depth $L$ as shown in the figure The ...
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