How Well Should One Know Physics After I and II?

[erok81]

Physics I and II being the first two calc based physics courses.

I am constantly worried about my physics knowledge after these two courses. So bear with me while I try to explain this...

The question: how well should one know physics after these two classes? Should I be able to solve just about anything mechanics/E&M related or are these covered more in depth later in the physics program?

I still can't really derive anything and I am nearing the end of the series. For example: if I was asked to derive the formula for the magnetic field in an infinitely long wire, I probably couldn't do it. I understand the example and see how it is derived, but like I said, couldn't do it on my own.

Also how much actual calculus did you (that have taken it) use? We've understand the material but that's about it. I haven't had to solve anything (test and homework) that required any integral calculations. There were a couple used in derivation examples, but that's it.


The main reason I am worried is because something my DE/linear algebra professor during class. He compared piano playing to math - math being able to understand some of the theories and how the math works rather than just solving problems. He said that being really good at math (like the previous sentence mentioned) is comparable to piano players that are really good from childhood, able to read music etc - I hope that makes sense, maybe a better word would be a piano playing prodigy? This eventually lead to him saying that being exceptionally good at math isn't something that can be learned; you either have it or don't - it cannot be learned.

I am fairly good at physics, but am stuck on the derivations and a few things from physics I that I have forgotten since.

Is it hopeless like my math prof has me thinking or is there a chance to learn this stuff in more detail later? Eventually getting better at this stuff?

 

[lisab]

Physics I and II are really just introductions to the material. Nearly everything you just learned, you'll see again in your upper division courses, then again in grad school. Of course each level will be deeper and more advanced mathematical methods.

If you can follow the derivations, that's great. It's important to do so, it develops your intuition. It takes a lot of exposure before you can become good at it.

I wouldn't take what your math prof said very seriously. We've had similar discussions on theses forums before, with students who believe that if they aren't the next Einstein there's no sense in studying science. Personally I think that's a very bad attitude; everyone has to work to learn this stuff, no one is born knowing it.

Consider your professor's piano prodigy analogy. I don't know if you've ever known a musical prodigy, but they study **hard** to learn their craft, usually many hours a day. What makes them special is that they are willing to put in that much effort at such an early age.

 

[jtbell]

Should I be able to solve just about anything mechanics/E&M related or are these covered more in depth later in the physics program?

They sure are! Look at the physics course listings and the physics major requirements on your university's web site. You'll probably find at least one intermediate or upper level course in classical mechanics, and a two-semester E&M sequence. You'll probably be required to take them for the major.

 

[Pengwuino]

After the first 3 semesters of your calculus based physics, you don't even know enough to know what you don't know. You probably don't know what an "Action" is, you probably saw Maxwell's Equations but really didn't truly DO anything with them, and you probably don't even know what Condensed Matter really means or how to actually do Special Relativity.

Programs are setup so that you're simultaneously learning the math and the physics. At this point, you can't delve into some more in-depth stuff because you don't have the math for it. You'll eventually get into Linear Algebra and Differential Equations and some Complex Analysis and you'll simultaneously get into more in-depth courses on Mechanics, E/M, Condensed Matter, Thermodynamics, and all that good stuff. Hell, after 4 years, even then you really don't know all that much. Enough to teach high schoolers and community college, but not enough for real original theoretical research or anything like that.

As for the piano/math that, it's true to a level of being a Fields Medal winner. I hate when professors say stupid things like that to impressionable people. Sure, to be the best of the best of the best you probably need to just be born with the ability to see mathematics in a special way that most people don't. But who cares. You'll want to be a Physicist. Even Einstein had to spend almost a decade just figuring out the math for General Relativity.

 

[erok81]

Thank you to the three of you. :)

That makes me feel quite a better. I was almost on the verge of switching over to engineering. ;)

I know I'll never be the next Einstein, but that's okay. I just want to know/understand the subject well. It also now makes more sense about the piano comparison relating to Fields Medal winner/Jr. Einsteins.

It's a huge weight off my shoulders that's for sure. Now I can get back to learning without this constant thought on my mind.

 

[JasonR]

I and II, IMO, really don't give any indication of how you'll do in physics. It can mostly only indicate that you SHOULDN'T be doing physics if you can't handle intro; I could easily see someone doing well in intro and then failing miserably in upper level. (Physics also seems to have a way of jumping right from 100 level to 300 level.)

You seem concerned about not being able to derive things; there's some things that are often presented in intro physics with minimal explanation that can make you freak out a bit (moment of inertia comes to mind) because it's beyond the physics and/or math you are expected to have when you are in intro.

This also bears on your seemingly not needing calculus: in my experience intro tends to be presented without calculus (so they'll hand you a result that would require an integration for instance) and if you're lucky they'll make a few brief comments about how to do something with calculus. I think this is a combo of people usually being in Calc I/II concurrently with Physics I/II so they don't want to lean on stuff you're just learning; and the fact that bio/premed/chem majors are often forced to take intro physics, but oftentimes they just put them in the physics department intro physics instead of a separate intro physics, so the physics and math people in the class might get frustrated with the mathematical simplicity, while the bio and premed people especially seem to often have trouble with high school trig-they're probably never going to take calculus so you can't make it integral to the class (pardon the pun).

Someone also suggested that you don't even know enough to know what you don't know after just intro, and I agree.

 

[nlsherrill]

Thank you to the three of you. :)

That makes me feel quite a better. I was almost on the verge of switching over to engineering. ;)

I know I'll never be the next Einstein, but that's okay. I just want to know/understand the subject well. It also now makes more sense about the piano comparison relating to Fields Medal winner/Jr. Einsteins.

It's a huge weight off my shoulders that's for sure. Now I can get back to learning without this constant thought on my mind.

Haha it seems like the physics students at other universities have the same inside jokes.

I'm in the same boat as you man. I do constantly worry that I don't know basic mechanics well enough for what I have taken. I think it really just takes years upon years of practice for most people to feel comfortable with the general problems and theorems.

Also your professors piano analogy is pretty bad in my opinion. While I do agree that to be someone like Edward Witten you do have to have natural talent, but to be someone that makes headway in their field of study requires dedication and commitment. And as a musician of many years, I have witnessed distinct difference between someone who can just "pick up the guitar and play" and someone who has some real creativity and art to create. I have seen people pick up guitars and within a year be able to play insanely technical music, but yet they can't write one memorable riff. But also, music and math are different..

Don't be discouraged. And definitely don't switch to engineering, or the physics majors will call you a traitor haha.

 

[JasonR]

With a physics degree you can do most engineering jobs if you're good enough at the physics. (You're probably only locked of fields that require you to have things like Concrete I, Concrete II, Concrete III, and Concrete IV on your transcript, and quite frankly if you did well in physics you'd probably be bored to tears doing stuff like that.) I don't think it works in the other direction though, or at least not nearly as often.

That and at a certain point engineering vs physics becomes a somewhat arbitrary distinction.