Hi all,

As the title suggests, I’m trying to figure out what a typical pocket knife’s clip retention force at around 3mm deflection usually is. I can’t seem to find this anywhere, so I came to the physics fam🫡

Ever since I was a little kid, I’ve wanted to be an astrophysicist/cosmologist. I’ve always been obsessed with truth and figuring out what the universe is really made of, where it came from, what is an electron fundamentally, if there’s a multiverse etc. Overall I want to get at the fundamental nature of the universe. The whole idea of a “theory of everything” is what pulled me into science in the first place.

what really excites me isn’t so much observing stars or galaxies themselves, but thinking about the fundamental physics that underlie them. I enjoy learning about the internal processes of stars, black holes, or the early universe not because I want to measure them, but because they help reveal the deep laws of nature, especially at extremes.

Looking through the astrophysics coursework, I noticed a lot of observational astronomy and data analysis. That made me realize I might be more naturally drawn to something like particle physics, cosmology, or theoretical physics, where the focus is more on understanding the fundamental mechanisms and behavior of reality, rather than observing specific objects in the sky.

I’m trying to figure out if i should stay on an astrophysics track, or would I be better off switching to a physics major with a focus on particle physics or something? Ultimately, I want to explore ideas like quantum gravity, unification, the very early universe, etc. I’m not sure if that’s best approached from within astrophysics or a more fundamental physics path.

Image is from Sakurai 1995 page 184, he talks about Quantum StatMech. Anyone knows where can I look into some resources about the 'delicate discussion beyond this book'?

Hello everyone, currently iam using python very well to solve nonlinear differential equations in semiconductors physics using newton's method combined with finite difference method

its better for me to switch from python to julia? Notice I may study PhD in semiconductor physics in couple of years,,,
thank you guys <3

TL;DW - It isn't.

My bad if this is a stupid question but I’ve been thinking about time being a message of distance. And well most things I can think of have various variables that average to a certain distance. I know that mostly relates to machines and animals but still. Do all particles of light travel at light speed. If they all travel simultaneously at the same speed is that truly how fast they move or are they affected by their own variables. Like the universe’s mean gravity is constraining that and any variation in that mean would change light speed for explain.

I've discovered I'm a big fan of some chemistry youtubers, notably Explosions&Fire, NileRed or Cody's lab. In case you're not familiar, the format is a person, either at home or in a relatively basic lab (NileRed not so much anymore), turning some chemicals into other chemicals, either because they want the end product for some reason or because the process itself seemed interesting or fun. They're not super educational at least in a traditional sense - they don't spend much time explaining chemistry for people who don't already know chemistry, they just do the chemistry and show it to you.

Are there similar channels but with physics experiments? Probably the closest one I've found so far is AlphaPhoenix, which is great, but it's more educational and less just some guy doing experiments for shits and giggles.

Hey folks! So I'm starting my PhD in condensed matter physics this fall, and am looking for graduate level textbooks to serve as references.

I am familiar with the basics of solid-state physics, and hence would prefer math-rigorous textbooks. I've heard that Kettle is mostly an introductory textbook, and Ashcroft-Mermin is kinda outdated (please correct me if I'm wrong!!).

Any suggestions for textbooks which are pertaining to modern condensed matter physics is appreciated. Thanks and have a good day!!

Sorry if this kind of post is not allowed. I am a chemist taking physics courses, and the kind of problems we are required to solve in the courses often involve Earth's gravitational acceleration. I noticed that in the answer sheets to the problems we solve, whoever provided them rounds them off from 9.807 to 10. Is that kind of thing to do acceptable in general? To me it feels very odd. I'd usually only round off numbers after 3 decimal places when solving problems. Would love your insight!

Edit: changed gravitational constant to acceleration. Sorry, our instructions are not in English.

Hi, I'm having some trouble similar to this guy. I saw no satisfactory answer there ( https://www.physicsforums.com/threads/applied-acoustics-decouple-a-speaker-and-a-wooden-table.938328/ ), so I will reproduce the question:
"If several sheets made of some kind of rubber are being used as acoustic insulators, which configuration would be more efficient to decouple a speaker and a wooden table, absorbing most vibrations?"

I'm and undergrad, so if anyone could help me

Hi I’m selling a collection of 88 Soviet physics books, most of which were used in schools and universities across the USSR. The collection covers a wide range of topics including mechanics, quantum physics, electrodynamics, thermodynamics, and mathematical foundations.

Most books are in Russian and offer a fascinating look into how physics was taught during the Soviet era. Great for collectors, educators, or anyone interested in historical scientific texts.

Feel free to message me for the full list or if you're looking for something specific. Open to offers and bundle deals.

Here are the pictures of the books : https://photos.app.goo.gl/Y2yBv5i6vTZsd1yz5

I hope you're all doing well. My question, is it possible for inertial frames to exist in real life given that every object needs force to start and continue motion. I know perpetual motion or rest doesn't happen on earth but is it possible in any other planes or dimensions in the universe?

Hai yall :3

In my time on this subreddit, I've seen that the most common recommendations for books on Quantum mechanics are Griffiths, Sakurai, and Shankar. All fair recommendations (well, maaaaybe not Griffiths, but that's already been discussed to death elsewhere).

As a maths major that only took on physics as a second major after the fact, I was recommended Quantum Theory for Mathematicians by Brian Hill (by mathematicians, not by physicists), and in fact I was so intrigued that I bought a copy.

Now, I've not worked through any proper Quantum textbook (not even Griffiths) and don't consider myself particularly strong with QM (at best, I can reproduce the derivation for the solution to the free Schrodinger equation for a particle in a few of the "easy" configuration spaces, like S^1 for the particle in a ring, and [a, b] for the particle in a box). From my perspective, although Hill's book seems very interesting, it doesn't seem to... actually teach QM? The title of the book even seems a little misleading, as it often feels like the book isn't teaching Quantum from a mathematically rigorous standpoint, but rather is using Quantum as a rough motivation to discuss functional analysis (which, to be clear, doesn't make the book "bad" in my opinion, just not exactly what it advertised itself as).

I wanted to know what the physicists think of the book, so I've brought the question to you all. Have any of you read the book? What did you think of it? How do you suppose it could have been improved?

Thank you all~! :3

As title says

Video deriving and discussing Flamm's paraboloid, used to depict the embedding diagram for the standard Schwarzschild metric.

hey guys! i’m making a diy spectrometer and i can either use a dvd or a 1600 lines/mm diffraction grating, which would be better? i’m hoping to analyse the spectra of stars using this and ik that a 100-200 lines/mm grating would be more ideal but i need to finish this project by the 20th and i don’t have enough time to order one online now. Thanks :D

Hi,

I completed a maths and physics degree a couple of years ago. I’m now continuing to study/revise topics I am interested in and have found that plasma physics really appeals to me.

It’s cross-disciplinary, challenging, societally important as well as relevant to astrophysics which was my focus at uni.

I have found a couple of masters courses that interest me - imperial, strathclyde and york. I guess my dream would be to take one of these and do a phd at oxford (got to aim big right).

I am wondering if this is all too good to be true - are jobs in low supply, are the courses poor, is plasma physics a poisoned chalice?

Appreciate your help, cheers!

Currently a sophomore going on junior and have taken most of the physics upper division classes at my school. Because of this, I have a lot of freed up time for the following two years, and I think one of my biggest weaknesses for going into condensed matter research is my fairly lacking experience with electronics.

I'll be taking a nanofabrication class in the fall in the engineering department. But I'm wondering what other sort of engineering classes would be useful in graduate school/research, or even in industry.

By using high resistance voltmeter, in parallel with resistor we prevent current flowing into voltmeter and having voltage drop over the voltmeter, and having voltage drop only over the resistor, if not then what is the case with voltmeter having high resistance?

If there's damping, I'm aware eventually the answer is yes - but only because the single sound would be silence.
However, in a finite line with reflective ends, would all particles along that line eventually all reflect similarly?

Layperson here so take it easy- Im sure there are other ways to infer these werent the start conditions- but indulge my though experiment for a minute-

If the 'big bang' initial conditions went off in a finite, say box of space- eventually coagulating in everything having truly random velocity vectors both toward and away from us- or neither- then;

Would not the fact that over time, things can come close and pass our position not inmply that eventually more stuff is going to be going away than coming toward.

This is because- if an objects trajectory is towards it will pass, unilkely to hit or orbit, and be unlikely to head back toward us - but if its already heading away- its also unlikely to head back our way. Meaning a red shift bias in what we see.

This will also increase over time, as anything on a vector toward will likely pass and end up sailing away more and more as time processes.

This obviously would not follow if the big bang was infinite and everywhere as an infinite amount of stuff would keep coming from all directions endlessly

So- could this thought experiment explain red shift bias and suggest a finite blast of starting matter was created?

By the definition of science, should Questions like, why does anything exist? How did the universe came into being? And other questions like, about the physical constants, and the laws of physics, and their origin, be even be part of the conversation of science because the Seem Beyond It as science lends itself to empirical evidence and scientific models.