# All Questions

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### Combining Moment of Inertia Tensors

In a physics simulation of rigid bodies, if I have a cube with a known mass and moment of inertia tensor, and I attach it to another cube with a known mass and moment of inertia tensor such that its ...
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### Examples of systems with linear response behavior

I've checking the linear response theory and there are 3 fundamental assumptions. 1) Linearity of the response of the system to an external excitation, 2) Stationary response function: ...
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### What unit would the answer be in?

So I have used this formula: $$W= PV_1 \times \ln\frac{V_2}{V_1}$$ and I have converted my values to cubic meters and pascals. So Work Done, $W$, what would be the unit for that answer? I already ...
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### Conceptualization and modelling of spin

I'm trying to get a decent understanding of the bell inequality, and so am trying to understand spin both conceptually and mathematically. When I picture spin, I imagine a sphere rotating about its ...
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### Maxwell's Equations for Accelerated Conductors

I asked a question about accelerated conductors in a magnetic field but nobody unfortunately answered. That is: Ohm's Law for Accelerated Conductors Maybe, I could not state my question well. I ...
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### the twin paradox [on hold]

about einstein twin paradox i don't understand how time will pass differently to one of the twins,it might feel differently but if i traveled to another country and got back in 2hours i might feel ...
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### Are Mathematics the language of the universe? [on hold]

I am a high school student and next year i am going to be a physics major, so this year i put all my effort on physics and mathematics, since it a great tool for physicists. But now i wonder, in ...
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### What would Negative Energy act like? [duplicate]

So I heard that if you want to make a wormhole you need negative energy. What is special about Negative Energy that allows it to do that? What are the properties of Negative Energy compared to normal ...
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### Scale factor and energy density

I'm looking at some solutions of the Friedmann equation at this website: Solutions to Friedmann equation If I look at the first problem (Problem 1: matter or radiation in a flat Universe) and click ...
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### Radially free falling observer [on hold]

I am a student. i read in a paper for a radially free falling observer in a Schwarzschild metric, the relation between the Unruh vacuum state and the proper time when the observer crosses the event ...
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### Physical Meaning Of $dQ/T$ Regarding Clausius Inequality: Is it related to Energy Loss in form of heat or Something Else?

What is the physical meaning of term $dQ/T$ in Clausius Inequality $dQ/T \le dS$ ? Physically we can relate entropy to number of microstates of a system, which relates to number of possible ...
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### Why does a cooling car engine crackle?

Why does a cooling car engine crackle? What determines the frequency of the crackles?
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### Can you debunk this “Perpetual” (ie, very long term) motion machine? [on hold]

In the following design, gravity is "always" pulling down. There's a parallelogram-shaped box containing a magnet, and underneath the lowest corner of the box is another magnet to repel the first ...
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### On which basis we think there is something more than just super dense matter in black holes?

Apparently physicists think that there is something inside black holes. Like a new universe or a link between dimension... But for me a black hole is no more than supermassive supercompacted matter. ...
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### Will this sail-based moving system work? Why? [duplicate]

So simple: Will this sail-based moving system work? Why?
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### Is there a binary black hole system in the middle of the galaxy?

We have observed gravity effects from black holes in the center of galaxies, but galactic centers are dusty so we can’t tell if it’s one black hole or two black holes in a binary system in there. A ...
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### Spontaneous symmetry breaking of SHO

Spontaneous symmetry breaking refers to the solution of a system loses some symmetry in its Lagrangian. Consider a Simple Harmonic Oscillator, its lagrangian is time translationally invariant but its ...
I am studying the course TPG4145 Reservoir fluids in NTNU and specifically the supercompressability factor $Z=\frac{V_{\text{real volume of the system}}}{V_{\text{ideal volume of the system}}}$ for ...