Other When is it time to throw in the towel?

[NicolaiTheDane]

So I'm at a point with my education, where I'm considering whether I'm actually smart enough to do this.

I'm taking Electromagnetism (using Griffiths 4.) and its just kicking my butt, in ways it has never been kicked before. The expected fluidity with the maths involved, some of which I have never encountered before, while at the same time treating it as trivial, is frustrating beyond belief. Not even mentioning the lack of steps between equation evaluations (not sure what its calling english. I mean where you show the steps you are taking, as you manipulate equations), makes reading pages or examples take several hours.

Its simply to abstract, and expects too much. I don't know what to do. I feel like I'm a haze from I wake till I go to sleep. I cannot think about anything else, yet I can't absorb new information, even in other classes which are relatively easy atm. I feel something like indifferent and terrified at the same time.

Have you guys ever experienced anything like this. Taking a class that got you to the point, where you weren't just afraid you won't understand/pass it, you know it. Did you get over it, or is this the time to quit physics?

 

[jedishrfu]

Hang in there, you seem to be hitting the proverbial upper level coursework wall. It happens to everyone. This because we glossed over lots of earlier concepts and now we are being hit with stuff we've seen before but in a more general way. Don't sit there, go out and talk with your classmates and the prof to get help.

One key to understanding electromagnetism is vector calculus needed to understand Maxwell's laws. You might need to get a Schaum's Outline on the the subject. Also Khan Academy and mathispower4u.com have videos related to vector analysis concepts that you really need to understand. For me the curl was the most confusing.

https://www.amazon.com/dp/B00AO1JM5O/?tag=pfamazon01-20

and this book by Schey:

https://www.amazon.com/dp/0393925161/?tag=pfamazon01-20

Perhaps you can detail the specific things that are confusing.

This site has some good short explanations of gradient, divergence and curl that may related to what you're learning.

https://betterexplained.com/articles/vector-calculus-understanding-the-gradient/

 

[NicolaiTheDane]

Hang in there, you seem to be hitting the proverbial upper level coursework wall. It happens to everyone. This because we glossed over lots of earlier concepts and now we are being hit with stuff we've seen before but in a more general way. Don't sit there, go out and talk with your classmates and the prof to get help.

One key to understanding electromagnetism is vector calculus needed to understand Maxwell's laws. You might need to get a Schaum's Outline on the the subject. Also Khan Academy and mathispower4u.com have videos related to vector analysis concepts that you really need to understand. For me the curl was the most confusing.

https://www.amazon.com/dp/B00AO1JM5O/?tag=pfamazon01-20

and this book by Schey:

https://www.amazon.com/dp/0393925161/?tag=pfamazon01-20

Perhaps you can detail the specific things that are confusing.

This site has some good short explanations of gradient, divergence and curl that may related to what you're learning.

https://betterexplained.com/articles/vector-calculus-understanding-the-gradient/

Your help is much appreciated, though I'm in doubt as to what I understand and what I don't myself at this point. Vector calculus is definitely part of it. I'm at that point with it, where I can perform it, and I understand the concepts, but I'm not fluent enough, so reading and manipulate equations of that sort is very taxing. For example the book seem to expect, that I can easily follow when it integrates by parts, while substituting using divergence theorem. I just can't and the physics of it all gets lost along the way. I can follow vector calculus stuff, but its no simple matter for me, especially the compact notations used (Not to mention Griffith's use of the ' mark, as differentiators, makes it 1000 times harder. I end up steering myself blind if $\mathbf{r}$, r, r', $\mathbf{R}$, R, and so on)

Its a mix of the physics of it all, as well as some math I have never seen before. An example of the mat, is it casually references legendre polynomials. something I have never heard of, nor can I find good explanations on it, and it just uses it trivially to help solve differential equations in spherical coordinates. I looked at page of an example (as the book teaches that part purely by example), for hours trying to deduce what the hell was going on, to no avail.

when it comes to the physics, for example I have no idea how to handle asymmetric objects for example. The book is somewhat good when it comes to extremely simple cases, like spheres, and infinite line charges, etc, providing plenty of problems and examples to understand and tackle. But on a test exam (none counting, merely to give us a feel for how we are at this point in the curriculum) I got this assignment:

Now obviously this is Danish, so the text is probably indecipherable, but as you can see we are clearly not dealing with something that simple. The cylinders are all conductors with a specified charge on them, and the first part assignment is to find some potentials of the picture a configuration, but I have no idea how to start. For instance will the charge on the rod, divide itself evenly under each of the cylinders (picture a)? What happens on the edges of the cylinders? the field cannot possibly only point radially, so my usually method of dealing with these problems are out. I just don't know what to do. I'm not asking to get help on the assignment btw, I merely use it to illustrate my problem. In this class I cannot seem to generalize the concepts. I merely learn how to compute case types. The concepts doesn't stick, and in many cases I cannot make sense them.

 

[jedishrfu]

Sometimes you just have to force yourself to do it by recipe without understanding the concepts behind it. I know I struggled with why the math works so well in physics.

Take a look at the better explained web pages and then check the khan academy stuff. The big thing is relating line integrals to surface integral and surface integrals to volume integrals.

https://www.khanacademy.org/math/multivariable-calculus/greens-theorem-and-stokes-theorem

ANyway, you need to do the recipe approach to prepare for your tests and then when you have time look for insight into these ideas. Work with your classmates in study groups to do this. That what we did in my college.