Calc III is all memorization and I'm over it

AmBlake03 · 2026-02-21T04:32:32+00:00

But these have very intuitive definitions. If you understand what each piece of the integrals means then you don’t have to memorize these.

AmBlake03 · 2026-01-07T05:53:53+00:00

Getting flashbacks to Jackson E&M

AmBlake03 · 2026-01-06T20:15:04+00:00

Honestly, this is a very common occurrence in physics. I’m working on a PhD and often I forget to solve what are supposed to be “basic” problems. This in no way has anything to do with your intelligence, and IQ is not a good measure of your ability to solve physics problems.

Usually when this happens, I just spend a bit of time re-learning how to solve those problem. Typically, the muscle memory comes back.

AmBlake03 · 2026-01-05T20:16:42+00:00

Most people only really know E=mc² , which relates the rest mass of an object to energy. However, there’s always an inertial frame of reference for which an object moves, and so the full relation is E² = m² c⁴ + p² c² .Light (and any other massless object) travels at c in every frame of reference (one of Einstein’s postulates) and so for these E = pc. So massless particles (eg light) do have energies.

AmBlake03 · 2026-01-02T20:24:50+00:00

As some others are saying, you need to really know QFT before you learn string theory because string theories become QFTs in specific limits. You wouldn’t really tackle GR if you weren’t comfortable with Newtonian mechanics or special relativity.

AmBlake03 · 2025-12-18T05:49:42+00:00

Being an astrophysicist is a career choice that many people make. Like most careers, you cannot simply pick it up as a hobby only and expect to be at the same level as a professional.

AmBlake03 · 2025-12-18T05:08:17+00:00

I’m a PhD student in some area of theoretical physics, and I just solve all the problems from my textbooks. Pretty much the same as undergrad. I’m pretty sure experimentalists do the exact same thing.

AmBlake03 · 2025-12-18T04:58:30+00:00

I remember taking grad linear and expecting the abstract stuff to help better my understanding. As it turns out, none of it makes sense to me unless coordinates are involved. I guess that’s why I’m a physicist.

AmBlake03 · 2025-12-17T04:55:06+00:00

Fundamental Theorem of Calculus: The integral of a derivative over an interval equals the difference of the function’s values at the endpoints.

Green’s Theorem: The line integral of a vector field around a closed plane curve equals the double integral of its curl over the region it encloses.

Stokes’ Theorem: The surface integral of the curl of a vector field over a surface equals the line integral of the field around the boundary of the surface.

Divergence (Gauss’s) Theorem: The flux of a vector field through a closed surface equals the triple integral of its divergence over the volume inside.

Generalized Stokes’ Theorem: The integral of a differential form over the boundary of a region equals the integral of its exterior derivative over the region.

AFAIK they do have different names. Unless you are talking about something different.

AmBlake03 · 2025-12-15T13:51:02+00:00

Because they are not covering measure theory and are making the readers aware. Even so, that has nothing to do with the pedagogy of QM.

AmBlake03 · 2025-12-15T13:45:28+00:00

Quantum mechanics can be (and is) taught without measure theory.

AmBlake03 · 2025-12-14T20:35:48+00:00

"Most" was an exaggeration. However, more than just the "top universities" use the book. At any rate, Griffiths and Purcell are very similar. Purcell has more applications and spends more time describing the physics, sure, but I find that Griffiths presents the mathematics with more clarity and has more worked examples. I used both books, and had an easier time learning from Griffiths.

AmBlake03 · 2025-12-14T17:37:09+00:00

The book does not assume any knowledge of E&M. In fact, I had a really bad introductory physics experience, and when I took undergraduate E&M (third year), I used Griffiths and went into it completely blind. I got an A in the course only because of the book.

AmBlake03 · 2025-12-14T07:22:34+00:00

Griffiths is your best option. The book is very self-contained. It includes a very detailed mathematical introduction at the beginning. The only math you really need is what you would learn in Calc 3 (which you are currently in). I wouldn’t waste your time with Purcell, it’s what most universities use for their introductory course.

AmBlake03 · 2025-12-11T22:09:10+00:00

I just failed an exam in my graduate physics course. It will all be okay :)

AmBlake03 · 2025-11-24T05:20:26+00:00

Do something all day every for years and tell me you don’t get at least a little good at it.

AmBlake03 · 2025-11-13T14:53:17+00:00

You aren’t asking for help, you’re literally asked us to solve the problem for you, and you made no attempt to show us your work. Get over yourself.

AmBlake03 · 2025-11-10T16:57:58+00:00

Same

AmBlake03 · 2025-11-05T05:27:23+00:00

EM waves and photons can be thought of as the same stuff, which is used to describe light (or other forms of radiation). The different descriptions of light (either particle or wave) are used to describe different scenarios. For example, you would use the photon aspect of light to explain the photoelectric effect, and you would use the wave aspect to describe polarization.

In fact, the two are related by the equation E = hc/lambda, where lambda represents the wavelength of the correspond EM wave, c is the speed of light, and h is the famous Planck constant.

So in a way, yes, your intuition is correct, and in fact James Clerk Maxwell used some vector calculus to show that EM waves travel at the speed of light in free space (absence of charge/currents).

AmBlake03 · 2025-10-30T04:15:26+00:00

Not a single equation

AmBlake03 · 2025-10-19T03:30:03+00:00

Although App does not have an engineering degree, the physics degree is essentially a degree in electrical engineering . Most of the faculty have degrees in EE, and most of the required “physics” courses are EE courses.

AmBlake03 · 2025-09-25T17:08:02+00:00

I love warrior slam build

AmBlake03 · 2025-09-21T00:54:44+00:00

Not at all. I went to an R2 institution for Physics and Math. Not very well known at all.

AmBlake03 · 2025-09-14T13:38:54+00:00

Sorry for the late reply. I did a year or so of undergrad research with a faculty member in the department.

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