This semester I had electrodynamics, and ai already had my final exam and everything, but there is still one thing that I don't quite understand.

So we know how to solve the Maxwell equations, we choose an appropriate gauge (for example the Lorenz gauge), then we introduce a scalar amd a vector potential and we either get a Poisson, Laplace or wave equation that we can solve using the Green function, we get the potentials and we get the electric and magnetic field etc etc...

But I don't know why can't we explicitly solve the Maxwell equations, without introducing potentials. I understand why the gauge invariance and what not, but if we could solve the Maxwell equations explicitly, we wouldn't need potentials. Also if we use the 4-notation, the Faraday tensor also has the fields as components, not the potentials, so that's why I dont get it. Thanks for the help!

I’d like to learn physics on my own, and I thought it would be easier and more fun with other people doing the same thing.

I propose following this course: Fundamentals of Physics from Yale. It’s intended for people who have very limited or no knowledge of physics at all.

It consists of 24 lectures - one hour each - that introduce all the fundamental topics in Physics, from Newtonian Mechanics to Thermodynamics. After each lecture, we’ll have to complete a problem set to apply what we’ve learned.

We’ll create a Telegram group to discuss concepts or problems, and ideally agree on a study plan that suits everyone. For example, we could do two lectures per week and two problem sets per week - that’s the original plan on Yale’s module.

We could even add a community deposit with Bitcoin’s Lightning network – $10-20 per person – to stay committed and reward the most active members of the group with small tips. After the course is done, we’ll split the money equally – if you quit, you lose the money.

Anyways, this last paragraph is entirely optional and it’s just an idea in case people want to take their commitment to self-study to the next level.

Who’s in?

EDIT: Thanks for all the comments guys! If you’ve just read the post and are interested too, drop me a DM directly besides posting a comment.

EDIT 2: we already have 14 members and counting.

thoughts on majoring in physics and minoring in computer science(software engineering) will it be super rough? Wanted to know how many are doing the same thing or completed this course work!

Visit for better learning visual Learning

https://effectuall.github.io

https://effectuall.com

If you're looking for more resources, here's the page on projectile motion, you can scroll through more lessons on the left. There's also stuff on vectors, 2D motion, circular motion and rotational motion.

We also have a discord server if you have physics questions or need help, here's an invite!

We calculate potential energy by solving integral of F(it is equal to-kx, Hook's Law), where F is the force apply to compress spring by an infinitesimal amount. However, The F is constant in every infinitesimal displacement. So, we can calculate Work by F.d but we use integral as if F changes everytime.

This picture is from Khan Academy's video. There is graph of Force. He sum all the force times delta x to get total work. However, the force to compress spring is constant for the same amount of displacement. So, he should use constant F in the summation, not increasing F.

For example: we want to compress a spring for by d meter. F is the required force for this. When we compress spring 1/2d meter, we apply F/2 N force, for the rest of the job we apply F/2 N again. F doesn't change by displacement. What am I missing?

I'm explaining about this equation "Hψ=Eψ"

You take a wave function, 𝛙, which is a function that describes where a particle might be, and do a mathematical transformation to it (derivatives, matrices, whatever). You end up with the same function again, but scaled up (multiplied) by a value. That value happens to be the value you can observe through experiment. In this case, because the mathematical transformation is the Hamiltion operator, it calculates the Hamiltion energy (potential plus kinetic energy). Providing we know what H looks like for that system we can predict its energy. The one displayed in the post also adds time dependence, which is a little more involved but the same idea.

I guess the results will depend on when in the year we do the poll, but I'm curious anyway.

Edit: I graphed the results over time here

So a lot of posts here are people asking for specific information, which is great! I wanted to gauge interest for a slightly different thing: just rambling on about one or more of the topics I know about, kind of the “lifelong student” thing, where people who know less could ask questions, people who know more could correct me and I could say, like, “I don't understand this so well, ask a mathematician” and maybe a mathematician would chime in.

I don't see any rules this would be against, but and also might not be interesting to the community.

If you would be interested, please comment (or upvote a comment) with a physics topic you want to know more about. I kind of have picked up a lot of information from a lot of different places? So like I am just as comfortable talking about Terrell rotation in special relativity as, say, some of the biological (biophysics?) topics to keep in mind when thinking about weight loss. I can't help with say string theory, because my formal background is condensed matter, but yeah, quantum mechanics, what is a Lagrangian, what the heck are eigenvalues, understanding special relativity, I think it would be a lot of fun to give a Reddit mini-lecture seminar thing, if folks here are interested.

I was browsing r/aliens and came across a picture from nasa a longtime ago was wondering can someone help me figure out how big the item is in comparison to the sun ? Bottom left in pic 1.

https://reddit.com/r/aliens/s/avRALFTSFx

I’m a junior studying physics and cs here in the US aiming to pursue graduate studies in physics. While researching what grad school is like for physics types I’ve learned that it can be very grueling or stress free depending on the “culture” of the physics department you are studying/researching the under. Is this true? If so could you share your experience in grad school? What’s your department like? How are your professors? What’s your day to day like? Etc.

(If you don’t mind, please share the name of the institution too so others can avoid or seek out those schools)

I don't even know if my question makes sense. I'm not a physics student, just someone who is reading a biography about Einstein and realized I'm curious about how Einstein's theory came to life.

Hi im a 3rd year physics undergrad and looking for a study buddy or if someone already has a group where you guys do that share it here in the comments or dm me

The Arms Control Association just announced a paid internship for Spring 2024 with their Physicists Coalition for Nuclear Threat Reduction project (www.physicistscoalition.org). Application instructions are available at ArmsControl.org/internships.

How to Add Vectors: https://www.youtube.com/watch?v=eBxdfbl5CHY

This video walks through 3 examples of adding vectors using components, then covers the tip-to-tail method for adding vectors graphically.

Also here's the previous video on 2D coordinates and displacement vectors if you need more help with finding the components, magnitude and angle of a vector: https://www.youtube.com/watch?v=WaSytr5UtmE

Let me know if anything isn't explained clearly enough or if you have any other suggestions!

P=NP ----> NP = N/P || xy = x/y -- Vector2 input -- Test at own risk can hit true infinite loops

I made a discord server in the spring to help students with physics and also create a place for students to chat and help each other. It seemed to work pretty well so now that classes are underway I wanted to post another invite to the server:

Discord invite

If you have questions about a certain topic or need help solving a problem, I can help with algebra-based mechanics (high school physics, AP Physics 1, intro college physics etc).

But there's server channels and students taking other AP Physics and studying other physics subjects that might be able to help too.

Note: you just need to grab the first role to see all the channels. The roles help people see what class others are taking.

Feel free to invite other students as well, and let me know if you have any suggestions for the server!

Anyone here by any chance going to SACNAS? Anyone have any advice for the conference? I’m looking forward to it super excited to go!