# All Questions

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### Prandtl's equation - Calculating coefficients

I don't even know how to get started. Could you please give me a clue? I haven't seen a similar problem before.
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### Does gravity change the pressure of a column of water when the column is tilted from horizontal to vertical?

I need to settle an argument. I think gravity causes a column of water to exert greater pressure against the walls of a pipe in which it is contained as it is tilted from horizontal to vertical. In ...
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### Motion in a Paul trap: $2n$th harmonic with larger amplitude than $n$th harmonic

Using a Paul trap, we captured the motion of a light charged particle (based on a rotating potential applied by AC current). Our rotational frequency was 50 Hz, and so when used FFT on the data, we ...
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### What happens when ice melts

Case 1: You take x litres of water and cool it to solid ice(say 0 degree) and measure the volume of ice as ...
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### constant c in Lorentz force

I met some of examples of force in studying classical dynamics, and Lorentz force was represented as $$\mathbf{F}=\frac{q}{c} \mathbf{\dot{r}} \times \mathbf{B}$$ I've searched for meaning of $c$, ...
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### Is it possible to use “negative sound waves” to “cancel out” a sound to create silence?

I saw youtube videos that claimed to do this, although I'm quite certain the videos just excluded sound and lied. However, I am wondering if the physics of this is actually possible - to create a ...
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### Why does a conservative force return the work done against it by a body to that body?

Newton's 3rd law of motion: Newton's third law of motion or the law of action and reaction implies that there is no isolated force in nature. Whenever there is any force at all , there must be ...
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### Why does light fade from a room?

So basically in my toilet I have this really bright ceiling light, but when I turn it off it doesn't just instantly plunge me into darkness, but rather sort of fades out over a few seconds. It looks ...
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### Can Newton's Law of gravity be deduced using dimensional analysis?

I tried using dimensional analysis to deduce Newton's law of gravity but I wasn't able to do so as one of the equations were $0=-2$ which is a contradiction. But I thought that we can't do that ...
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### Why magnetic field lines and force are not orthogonal with magnets?

The below explanation why magnetism exists is superb in this video. The explanation about magnets is also great in this video. A magnet has atoms with unpaired electrons forming mini magnets. The ...
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### Interferometry works as a filter

I attended an astronomy seminar the other day and though I did not pick up much as it was on data collection etc, I did take away one sentence: "Interferometry works as a filter" Now I know what ...
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### What is the physical meaning of anti-commutator in quantum mechanics?

I gained a lot of physical intuition about commutators by reading this topic. What is the physical meaning of commutators in quantum mechanics? I have similar questions about the anti-commutators. ...