General Q&A about physics of any type and at any level
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My optician counselled me I don't recommend a 1.74 index with a metal grooved frame, like the one you want from ic! Berlin, because the edge will be less resilient and be more susceptible to chi...
Which one is correct? $$E=mc^2$$ or $$E^2=(mc^2)^2+(pc)^2$$ I mostly seen $$E=mc^2$$ from my childhood, and when I was learning problem solving in relativistic mechanics I had seen $$E^2=(mc^2)^2...
Lets say we have a mass connected to a spring.Assuming not any friction the ODE which describes the system is $m\frac{d^{2}x}{dt^{2}} = -kx$ We can set 2 Dirichlet boundary conditions $x(0)=0$ an...
Maxwell's first law in differential form states that $$ \triangledown \cdot E = \frac{\rho}{\epsilon_{o}} $$ . In case of 1d can we say that $$\rho = \lambda$$ where $$\lambda$$ is the linear char...
I'm trying to understand the uncertainty principle and its implications for particle measurement. From what I've read, it seems that the principle states that we cannot simultaneously know the exac...
With time dilation a cosmonaut could travel forth in time, especially in light speed. But are there much lesser speeds which might be achievable by humans in the next 100 years which could also in...
If we have a LC high pass filter the transfer function H(s) becomes: $$ 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...
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...
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...
What examples of a system can be described by a system of ordinary differential equations?
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...
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....
Suppose we have an electric dipole of charge Q+ and Q-.The charges of the dipole are fixed (they cant move closer to each other than they already are).If we place a test particle at some distance r...
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. $$L=T-U=\frac{1}{2} m\dot{x}^...
I have recently heard of Apsidal Vectors. I was searching about it through internet. I had found the video in YT. I had found similar question in PF. But, the PF answer wasn't clear to me. I am jus...
Would a colony on earth's moon need to be deeply underground to ensure more natural gravity (by getting closer to its core)?
I was looking for equation of motion. I came up with a solution but it doesn't satisfy me. Cause I was trying to find motion of that particle using Lagrangian. We know that $$W=\int \vec F\cdot d\...
$$\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...
Please see the images below. I owned these Mykita John glasses for three years, which feels short for glasses to break! Every day, I fold them them before placing it on my night stand and going to ...
Are there areas in the observable universe which surely cannot contain galaxies with planets that can support life as we know them?
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...
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 "...
We commonly say that something has a weight, which is synonymous with a mass. Things have a weight because the force of gravity is relative to something’s mass. Subatomically, what is mass? There ...
Since, there's no book category currently so, I am asking it here. And, It can be moved to that category later. I want to start learning now so, I don't want to wait. Which book is best for Clas...
Is this advice correct? Are they alluding to Freezing Point Depression? Adding salt to tap water lowers the Crystalloid's freezing point. Pour 3 tbsp (51 g) of salt into each of your 3 plast...
If planet 9 exists, is it correct to say that it is a "dark planet"? By "dark" here I mean to a planet that doesn't reflect enough light to easily be seen from normal telescopes (in the current co...
How can I turn this floor lamp into a reading light? I want all light exiting upwards from the lamp shade to point down. Do I just buy a mirror and put it on top of the lamp shade? Then the mirror...
Decibel level listed of solfege. Do Re Mi Fa So La Ti Do 24 27 30 32 36 40 45 80 I saw that whispering decibel level is around 40. And, normal voice level is ...
I don't understand either of these Reddit comments that are still too complicated. Please simplify? Alfenhose An interesting phenomena, it is because the brain doesn't store what you saw during ...
I was looking for book on classical thermodynamics. I found lot of related posts in PSE but couldn't find a book which type I was expecting. I was searching for book which covers the whole thermody...
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...
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...
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...
Two weeks ago, my carry on worked perfectly. But last week the detachable wheels stopped rotating smoothly, when I tried to glide my carry on. The wheels budge JUST A TAD when you push them hard, b...
I stumbled these pictures on Quora, and I'm assuming they were real. Wouldn't the supporter (person whom gun is mounted on) suffer hearing loss? Wouldn't the barrel burn his ear? I'm assu...
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...
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...
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...
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...
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...
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...
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...
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...
I'm not asking about cleaning human organs here. This handheld power scrubber looks like your average rotary toothbrush! Indubitably I know that a toothbrush's brush head can be far gentler than...
IKEA discontinued this NOVEMBER lamp in 2007, but I still use it. IKEA confirmed that they did not intend or design any cover or share with this lamp, and the light bulb is supposed to be exposed. ...
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...
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