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Q&A

General Q&A about physics of any type and at any level

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Presuppose that I need vinegar of $c$ concentration, where $c$ < any concentration listed below. Let $w$ be the price of water that I'll use to dilute. How do I deduce which concentration (of V...

1 answer  ·  posted 4mo ago by TextKit‭  ·  closed 3mo ago by Mithrandir24601‭

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Suppose we have a gravitational wave which obeys the equation: $[G_{tt}-c^{2}G_{xx}]h_{\mu\nu}=0$ Lets take the case where $h_{\mu\nu}\ne0$ so we are left with the classical wave equation.Suppose...

0 answers  ·  posted 6mo ago by Volpina‭

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I'm trying to understand the uncertainty principle and its implications for particle measurement. From what I've read, it seems that the principle states that we cannot simultaneously know the exac...

0 answers  ·  posted 8mo ago by Reinstate Monica on Stack Exchange‭

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There are a couple different types of indoor air humidifiers. Most notably, the naive steam humidifier with a heating element, and then ultrasonic humidifiers. Now, heating water to create steam o...

1 answer  ·  posted 2mo ago by Iizuki‭  ·  last activity 2mo ago by Olin Lathrop‭

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Suppose we have a free falling object inside a planet's gravitational field with strength g.The planet's atmosphere provides a drag force which is dependant from the u^2 of the particle. Suppose t...

0 answers  ·  posted 1y ago by MissMulan‭  ·  edited 1y ago by MissMulan‭

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Say we have a four underwater components tidal power / hydro power system. Component A. A propeller would always orient along the same direction regardless the direction of the flow. This is th...

0 answers  ·  posted 1y ago by HolyDamn2.0‭  ·  edited 1y ago by HolyDamn2.0‭

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The general formula for a EM wave (solving for the E field) is: where $\varepsilon = \varepsilon _{r}+j\frac{\sigma }{\omega }$ My professor told me that the conductivity of vacuum is 0 so we...

0 answers  ·  posted 1y ago by MissMulan‭

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Suppose we perform the double slit experiment , but we fire instead 2 electrons instead of 1. In the double slit experiment performed in the 1920s a interference pattern was observed at the screen...

0 answers  ·  posted 1y ago by MissMulan‭

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Starting from the classical osmosis experiment, a U-shaped tube with a semi-permeable membrane, I would like to consider the case when the solute added to one of the compartments (labelled A) is co...

0 answers  ·  posted 4mo ago by Joce‭

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In the context of quantum field theory, why is it impossible for two photons (or other massless bosons like gluons) to collide and produce a single photon? This kind of a process is supposed to be ...

2 answers  ·  posted 6mo ago by Technically Natural‭  ·  last activity 6mo ago by Derek Elkins‭

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Please see below screenshot of 15:59.The LED spot light (fastened to the front of the boat) illumines merely a few meters in front, and fails to illumine most of the water between the boat and the...

1 answer  ·  posted 1y ago by TextKit‭  ·  last activity 1y ago by Olin Lathrop‭

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Lets say we have a mass connected to a spring.Assuming not any friction the ODE which describes the system is $m\frac{d^{2}x}{dt^{2}} = -kx$ We can set 2 Dirichlet boundary conditions $x(0)=0$ an...

1 answer  ·  posted 6mo ago by Volpina‭  ·  last activity 6mo ago by Technically Natural‭

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When a pendulum made of a conducting material moves through a magnetic field, it's a well-established fact that it experiences a retarding force, thus slowing it down, however, I'm unable to unders...

1 answer  ·  posted 1y ago by esrdtfghjk‭  ·  last activity 1y ago by Olin Lathrop‭

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The title is a framing for a theoretical question; I'm not asking for practical advice. A friend was recently in this situation and my attempts to apply what I remember of a couple semesters of co...

1 answer  ·  posted 1y ago by Monica Cellio‭  ·  last activity 1y ago by Olin Lathrop‭

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Suppose we have a arc of charges with some charge density $\lambda(\theta) = sin\theta$.I am using polar coordinates for convenience.But how can I find the direction of the unit vector of the net e...

0 answers  ·  posted 1y ago by MissMulan‭  ·  edited 1y ago by samcarter‭

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My optometrist said that round eyeglass lenses are OPTICALLY better than rectangular, particularly to correct myopia. He was NOT referring to fashion or style. I couldn't understand his explanatio...

1 answer  ·  posted 1y ago by TextKit‭  ·  edited 1y ago by TextKit‭

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Gravitational waves can be derived from the non-linear Einstein field equations and since they are by definition waves they must obey the wave equation: $u_{tt}=c^{2}u_{xx}$ but in General Rela...

1 answer  ·  posted 6mo ago by Volpina‭  ·  last activity 6mo ago by Mithrandir24601‭

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At home daily, I need to mix my table salt + COLD tap water. As "Marine salts dissolve faster and more thoroughly when added to circulating water," I "use a powerhead to speed up mixing time — my V...

2 answers  ·  posted 10mo ago by TextKit‭  ·  last activity 5mo ago by matthewsnyder‭

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Suppose a ferromagnetic material with initial magnetization $M_o$.Is there some specific formula which calculates the total magnetization $M$ as a function of $M_{o}$ and the Curie temperature $T_{... 1 answer · posted 1y ago by MissMulan‭ · last activity 6mo ago by Anyon‭ 25% +0 −4 Question I was wondering what force make drop slow down? Does every time a drop push toothpick back into bottle? And of course how to solve it. Struct This is a bottle be pierced by a wooden too... 0 answers · posted 9mo ago by Dead_Bush_Sanpai‭ · closed 6mo ago by ArtOfCode‭ 25% +0 −4 I need to separate these two parts, the opposite of the GIF below. While my hunky husband was lifting the chair up, and my brawny brother pushing the frame down, I kept hitting the top of the slid... 0 answers · posted 1y ago by Este‭ · closed 1y ago by Monica Cellio‭ 60% +1 −0 I'm interested in knowing the surface temperature of both sides of a double-pane or triple-pane window. Given the R-value of the window, and the air temps outside and inside, how can I calculate t... 1 answer · posted 2y ago by re89j‭ · last activity 2y ago by Olin Lathrop‭ 71% +3 −0 Momentum is proportional to an object's velocity, and kinetic energy is proportional to the square of its velocity$\dfrac{mv^2}{2}$. It's pretty intuitive that if object B is going twice as fast a... 3 answers · posted 2y ago by gmcgath‭ · last activity 2y ago by celtschk‭ 60% +1 −0 I was wondering what's the physical meaning of Laplace operator.$\vec\nabla$actually represent a field. I had seen that Laplace operator is written as$\vec \nabla \cdot \vec\nabla=\nabla^2=\Delt...

1 answer  ·  posted 2y ago by deleted user  ·  last activity 2y ago by deleted user

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Get 2 conductors and seperate them we can use Gauss's law to calculate the capacitance created by the seperation of the 2 conductors.Can we use other laws of electromagnetism to calculate the induc...

2 answers  ·  posted 1y ago by MissMulan‭  ·  last activity 1y ago by TonyStewart‭

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\begin{alignat}{2} && \vec \nabla \cdot \vec D & = \rho_f \\ & \implies &\int_V \vec{\nabla} \cdot \vec D \mathrm d\tau & = \int_V \rho_f\ \mathrm d \tau \\ & \impl... 1 answer · posted 2y ago by deleted user · last activity 2y ago by deleted user 57% +2 −1 What are the SI units of the wavefunction Ψ(x).I know that [Ψ(x)]^2 describes the probabilty of finding a quantum object at a certain quantum state but what about the wavefunction instead? 1 answer · posted 1y ago by MissMulan‭ · last activity 6mo ago by Anyon‭ 50% +0 −0 With time dilation a cosmonaut could travel forth in time, especially in light speed. But are there much lesser speeds which might be achievable by humans in the next 100 years which could also in... 0 answers · posted 1y ago by deleted user 25% +0 −4 Im designing a capacitor and I have decided to make the surface of 1 plate of the capacitor bigger than the other plate. How are the charges sorted through A2?Are they spread out to cover all th... 0 answers · posted 1y ago by MissMulan‭ 66% +2 −0 What will happen if an electron and a proton collide? They attract each other inside an atom. But, why they don't collide inside atoms? Does the "boundary" of the nucleus push them away? depends... 2 answers · posted 2y ago by deleted user · edited 2y ago by deleted user 50% +0 −0 Maxwell's first law in differential form states that \triangledown \cdot E = \frac{\rho}{\epsilon_{o}} $$. In case of 1d can we say that$$\rho = \lambda$$where$$\lambda$$is the linear char... 1 answer · posted 1y ago by MissMulan‭ · last activity 1y ago by celtschk‭ 42% +1 −2 Are there areas in the observable universe which surely cannot contain galaxies with planets that can support life as we know them? 1 answer · posted 2y ago by deleted user · last activity 2y ago by Olin Lathrop‭ 50% +0 −0 I had a thought that crossed my mind a while back that went something like this: It's a cool thing measurements exist, if there wasn't, there'd be trouble and we'd be counting atoms if we could.... 0 answers · posted 2y ago by General Sebast1an‭ · closed 2y ago by Mithical‭ 25% +0 −4 These WorldFamous companies advertise that their lenses can control myopia for kids, NOT adults. But none of these lenses are approved by FDA. I asked my optometrist why merely kids, not adults. Bu... 1 answer · posted 1y ago by TextKit‭ · closed 1y ago by Mithical‭ 66% +2 −0 We have place a charged particle of 2C with mass 2kg, 1mm above a current-carrying wire of 1A.The charged particle has an initial velocity of 100m/s The magnetic field of the wire for simplicity w... 0 answers · posted 2y ago by MissMulan‭ · edited 2y ago by MissMulan‭ 60% +1 −0$$F=F(q,p,t)\frac{dF}{dt}=\frac{\partial F}{\partial q}\frac{\partial q}{\partial t}+\frac{\partial F}{\partial p}\frac{\partial p}{\partial t}+\frac{\partial F}{\partial t}=\frac{\part...

0 answers  ·  posted 2y ago by deleted user  ·  edited 2y ago by deleted user

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Part 1 Say we have a round water pool, the radius is 10m, and the water depth is 2m. C is a fixed point: Fixed on the surface of water. Fixed at the center of the pool. F1 is stable forc...

2 answers  ·  posted 1y ago by HolyDamn2.0‭  ·  last activity 1y ago by Mithical‭

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What is semiholonomic is? Holonomic actually means two point can be expressed by a equation. Non-holonomic can be expressed but, not properly. Holonomic e.g. $r^2-a^2=0$ Non-holonomic e.g. $r^2-a... 1 answer · posted 2y ago by Anonymous‭ · last activity 2y ago by HDE 226868‭ 50% +0 −0 How to derive the Lagrangian differential force? $$\frac{d}{dt}(\frac{\partial L}{\partial \dot{x}})+\frac{\partial L}{\partial x}=0$$ I was trying to do something. $$L=T-U=\frac{1}{2} m\dot{x}^... 1 answer · posted 2y ago by deleted user · last activity 2y ago by celtschk‭ 60% +1 −0 In the lab I changed the angle the light hits a photoresistor and it doesnt obey Lambert's cosine law the conductivity of the photoresistor drops fast from +-20 to +-30 degrees angle.Why? 1 answer · posted 2y ago by MissMulan‭ · last activity 2y ago by Olin Lathrop‭ 50% +0 −0 If we have a LC high pass filter the transfer function H(s) becomes:$$ H(s) = \cfrac{sL}{sL + \cfrac{1}{sC}} $$If we solve for s to find a pole of the transfer function we get:$$ s = j \cfrac... 0 answers · posted 1y ago by MissMulan‭ · closed 1y ago by MissMulan‭ 50% +0 −0 What examples of a system can be described by a system of ordinary differential equations? 1 answer · posted 1y ago by MissMulan‭ · last activity 1y ago by Olin Lathrop‭ 50% +0 −0 I have recently heard of Apsidal Vectors. I was searching about it through internet. I had found the video in YT. I had found similar question in PF. But, the PF answer wasn't clear to me. I am jus... 0 answers · posted 2y ago by Anonymous‭ 42% +1 −2 Is it plausible to desire a "universal" calendar applicable everywhere in our universe? Must calendars be based on solar systems (Must calendars be "relational")? It might be that the universe "... 3 answers · posted 2y ago by deleted user · edited 2y ago by Trilarion‭ 60% +1 −0 We know that electrons always repel electrons. But, if somehow they collide, then what will happen? I found a related question of above one in Quora. An incoming electron can instead make them ... 0 answers · posted 2y ago by deleted user 25% +0 −4 Suppose we are using a force gauge to measure gravity in a planet. We set the gauge force to the 1N range which has a resolution of .01 N. From its specs the error introduced during the measurmen... 0 answers · posted 1y ago by MissMulan‭ 60% +1 −0 In my notes from University the reason a material can exhibit superconducting properties is at really low temperatures electrons form Cooper pairs of which the electrons of the Cooper pairs have lo... 0 answers · posted 2y ago by MissMulan‭ 50% +0 −0 I saw following equation in Griffiths EM $$V(r)=-\int_\mathcal{O}^r \vec E \cdot d\vec l$$ While the surface was closed but not symmetrical circular. At first I was thinking$\mathcal O$was repr... 1 answer · posted 2y ago by deleted user · last activity 2y ago by deleted user 33% +0 −2 I never grokked the optics behind LightHouses and the WW2 poster below work. LightHouse beams are narrow and focussed. Doubtless, the light source can fail to illumine a seafarer or the enemy subm... 1 answer · posted 1y ago by TextKit‭ · last activity 1y ago by Olin Lathrop‭ 50% +1 −1 I was looking for equation of motion. I came up with a solution but it doesn't satisfy me. Cause I was trying to find motion of that particle using Lagrangian. We know that$\$W=\int \vec F\cdot d\...

1 answer  ·  posted 2y ago by deleted user  ·  edited 2y ago by deleted user