How To Fix My Weak Physics Foundations?

[EnlightenedOne]

Hello PhysicsForums!

I am a Physics/Math double major undergraduate junior. I've always loved math, and to study the universe; so I decided to combine both and become a physicist! I did my Gen Phys 1-2 (with Calc) and most of my math at a state college and then I transferred to a university last fall. See below of the courses I've taken or am taking. Although I have a 4.0 GPA, I've felt for a while that my physics foundations were somehow "lacking". I'm saying this because now that I'm at a higher level I feel often that I can't even do some Phys 1/2 level problems either because it's been too long since I used them, or because my professors at the state college were kind of lazy and didn't really teach the topics too well back then; and I think it is both. This is just an example but my Phys 2 prof really did a crappy job of teaching us Electricity and Magnetism, and we all failed the test on it (it was really bad) so he dropped the test, but that doesn't help my understanding of it (I feel similarly weak in many other areas of basic physics)! Every time I'm trying to solve a hw/exam problem in my current courses I feel like my physics foundations are just not strong enough; it seems like everyone else somehow got a better understanding back in Gen Phys. At the point I am at, you HAVE to have a very strong and sturdy physics foundation, otherwise everything will collapse; which is what it feels like might be happening to me. My physics basics are not as developed as they probably need to be. And the courses I'm taking only get tougher from here... This occasionally happens with math in regards to physics, but not nearly as often.

So, it's hard to put it into words, but is there some way I can "fix", "restructure", or "rebuild" my physics foundations so that I can better continue my physics path?

It kind of feels like trying to build a large building on a mediocre or lacking foundation, and it's starting to show. Is there anything I can do? This has lately caused me a lot of discouragement on the physics path.

Also, has anyone else ever felt this way? If so, how did you get through it/fix it?

If you need me to explain more just ask.

Thanks!

Courses related to Math/Physics I've taken (I think this is all of them, but there might be one I forgot):
Math:
College Alg., Trigonometry, Pre-Calc, Calc 1-3, ODE, Linear Alg,
Foundations of math (currently).

Physics:
Intro to Phys, Gen. Phys 1-2 w/ Calc, Modern Physics, Classical Mechanics (currently), and Astrophysics I (currently)

 

[jedishrfu]

Its probably not that you have a poor foundation but rather things change as you get into upper division courses. Introductory Physics is often taught like a cookbook. As an example, you're given a formula for each case you might run into and to succeed you need to remember what formula a given case and under what conditions.

CM is perhaps the first general course you take where you find the conditions come from the geometry of the case and the constraints you put on the problem. EM is in a similar boat, Introductory Physics would teach formulas for specific cases whereas in EM you would use Vector Calculus and various constraints to derive those formulas.

Your best bet is to really focus on CM (since you're taking it now) and compare and contrast CM problem solving with problems from Introductory Physics so that you can clearly see how the conditions and constraints were defined.

 

[EnlightenedOne]

Its probably not that you have a poor foundation but rather things change as you get into upper division courses. Introductory Physics is often taught like a cookbook. As an example, you're given a formula for each case you might run into and to succeed you need to remember what formula a given case and under what conditions.

CM is perhaps the first general course you take where you find the conditions come from the geometry of the case and the constraints you put on the problem. EM is in a similar boat, Introductory Physics would teach formulas for specific cases whereas in EM you would use Vector Calculus and various constraints to derive those formulas.

Your best bet is to really focus on CM (since you're taking it now) and compare and contrast CM problem solving with problems from Introductory Physics so that you can clearly see how the conditions and constraints were defined.

Thanks for the reply! Yeah that sounds about right. It definitely and suddenly changed from "here's a formula (never mind where it comes from) and here's where you use it, and I'll give you all the numbers" to "Here's a few general symbols (like m, l, x, v) and some constraints and now find a general expression for the... (Basically derive the formulas)". I was expecting that transition to happen smoother but I guess it doesn't for most people. And of course, you have to have the basics down if you are to derive anything in these classes.

I have been and will continue to study hard in CM. Looking back at the introductory physics while in CM definitely sounds like a good idea, thanks!

 

[jedishrfu]

My favorite part of CM was my introduction to Lagrangian Mechanics. I thought it was quite novel and amazing that simply using the energies of the system one could find its motion. However my excitement was short loved as we pressed onward ever faster through the problem sets and I couldn't keep up like I wanted as I was working part time.

 

[EnlightenedOne]

My favorite part of CM was my introduction to Lagrangian Mechanics. I thought it was quite novel and amazing that simply using the energies of the system one could find its motion. However my excitement was short loved as we pressed onward ever faster through the problem sets and I couldn't keep up like I wanted as I was working part time.

My CM class is about to head into Lagrangian Mechanics so that's cool. But, yeah I totally understand how things can get overwhelming in school especially with any kind of job...

 

[gleem]

From what you said about your first encounters with physics especially EM I might be concerned too. That said though you can't start over again but EM being so important perhaps you could sit in on the University course as a refresher to see if you did miss something. Don't worry about not being able to do Physics I or II problems.at this point you do forget but advanced courses will give you and opportunity to recover. CM is a great course for seeing how a physics topic is developed at an advance level. You can judge your future successes with this course. I assume you will be taking an advanced undergraduate EM course at some point. This course usually reviews the basics of your Physics II exposure to this subject albeit at an accelerated pace before taking you into the intricacies of the EM interaction.

 

[EnlightenedOne]

From what you said about your first encounters with physics especially EM I might be concerned too. That said though you can't start over again but EM being so important perhaps you could sit in on the University course as a refresher to see if you did miss something. Don't worry about not being able to do Physics I or II problems.at this point you do forget but advanced courses will give you and opportunity to recover. CM is a great course for seeing how a physics topic is developed at an advance level. You can judge your future successes with this course. I assume you will be taking an advanced undergraduate EM course at some point. This course usually reviews the basics of your Physics II exposure to this subject albeit at an accelerated pace before taking you into the intricacies of the EM interaction.

Thanks for the reply! Yes, I will eventually be taking an advanced undergraduate EM course. I feel already like I've learned so much more from my current CM class that I have in any other physics course I've taken. That being said though, I've been struggling in the class lately because every problem I encounter in CM has some hidden piece of info that, unless you know it, you can't solve the problem, and you only know that piece of info most of the time if you remember it from Phys 1 or 2. I've also had a very hard time lately doing any of the problems with any kind of speed whatsoever (takes me forever to do my hw)... I just took a CM exam last week and I feel I did horrible on it, even though I think it was a fair test (I should know how to do it). If all that isn't enough, at least 70-80% of the time I don't draw the pictures for the problems right (can't visualize what's happening correctly), I try too hard on the easy problems and too little on the hard ones, and I almost always don't know that "one thing" you have to realize in order to do the problem. When I start a problem, I always feel like I know nothing about it and I'm still expected to do it right and fast. I don't know if others feel this way, but it doesn't feel good (it's very overwhelming, stressful and discouraging). I feel like there should have been some intermediate-level classes between the intro courses and the more advanced ones I'm getting into; it just seems like too much of a jump for such a hard subject.

 

[Stephen Tashi]

So, it's hard to put it into words, but is there some way I can "fix", "restructure", or "rebuild" my physics foundations so that I can better continue my physics path?

Work or volunteer as a tutor for physics. Answer physics questions on the forum. Trying to teach a subject is an excellent way to fix your own misunderstandings!

 

[atyy]

Read and do all the problems in the classical mechanics texts by Kleppner and Kolenkow and Landau and Lifshitz. For entertainment you can read the classical mechanics text by Fetter and Walecka. (I'm kidding about doing all the K&K problems, just do a few, most of them are way too hard unless you are a masochist, in which case I've heard Morin's text is good. you can skip the special relativity chapter in K&K. L&L have a reputation for being hard, but they are not, it just looks hard because the print is small. L&L are the best and keep all their explanations short and sweet. But you must master classical mechanics at the level of K&K before reading L&L.)

 

[gleem]

I'm curious but what text are you using? Also you should talk with your fellow classmate about how they view the problems and tests. Find a few people who you can work with. they may be able to give you some pointers that will help.

 

[deedsy]

I remember frequently being very frustrated in CM, because it seemed like every problem required some 'trick'/random assumption (turned out, most of the class felt this way too). I'd spend hours working on a problem and have nothing to show for it. After awhile (I'm a senior now) you just get exposed to these little tricks so much that they don't really hold you up anymore. You start making your own 'random' approximations/assumptions naturally.

 

[jedishrfu]

Yeah, I remember that too but then realized the one who first solved the problem had the same issue or that the problem was worked out backward from that same insight.

For me the most memorable one was to determine the ratio of time it took an object from space to fall halfway to earth. We had to find a connection between distance, time and gravity. Eventually the trick was hinted to us to be Kepler's law of equal areas in equal times and using the notion of collapsing the orbit into a straight line. I think the result was it took 5/9 of time for the object the fall the first half of the distance. That problem still haunts to this day. It would never have occurred to us to use Kepler's laws.