Note: took this class under remote conditions; hopefully, the reader is taking it in-person :)

TLDR: Gelmini wants everyone to learn and is quite helpful but her exams are freaking impossible.

Professor Gelmini is very enthusiastic and is always looking to help as much as possible. She is also very welcoming to feedback and is always trying to improve. Her office hours are very helpful, as she encourages questions and loves to see people finally understand things. She's very "motherly" and is a warm, wholesome person. One thing Gelmini lacks, however, is the ability to understand how much students actually understand the material. Professor Gelmini thinks we are all experts with the material. If she says an exam is meant to take an hour, it will probably take 3+ hours. Her first midterm was ridiculous, because it was literally find the formula in the notes, do some calculus on it, and get credit. If you didn't find the formula and tried to start with first principles (like the conservation of momentum), you wouldn't be able to solve anything. However, she curved that midterm very gently. And as always, she improved her second midterm (which was 24 hours). Even though I hate taking 24-hour physics exams (it's like 24 hours of torture), I think the questions on her second midterm were much fairer (although, the grading was a bit sus). Her final, however, was on another level. It was 24 hours of pain. I can't believe she gave that final. Worst part about it, the median was way to high. I wonder why.
Anyway, Gelmini is a solid choice. Her exams are super tough, but I think this is the class where I have learned the most physics (so far). Good luck!

This is a very, very difficult class, but it's rewarding: you will learn a lot if you are genuinely interested. Professor Gelmini's lectures are clear, her notes are incredible, and she's very helpful if you ask her something in lectures or office hours. The tests are brutal; the average in our first mid-term was about 30%. The homework is extremely difficult too (15-20 pages of solutions, requiring 8-12 hours), but the problems are exciting and they help you acquire a deep intuition for the concepts. I cannot emphasize how much taking the physics 1 honors series helped. Make sure you're very comfy with Linear Algebra before taking this class. 10/10 would recommend for anyone who's invested enough to put in a lot of effort. It was probably my favorite class I've taken at UCLA so far.

Gelmini is great! She is a very nice human being and does cool research! She loves it when students talk to her and she is always ready to reach out and help. This class showed me a lot about what physics is really about, and how math beautifully ties it together. She has a strong emphasis on visualizing problems, and her notes are beautifully written (and illustrated!). I would recommend using Thornton & Marion and also skimming through Taylor for chapters that T&M handles poorly (by assuming you know a lot more math than you probably do). Both texts develop the math where it's necessary, but I wouldn't discourage revising your linear algebra skills. Would definitely take this class again! P.S. she did go through relativity rather quickly but that being said, you really should just read the textbook and do hella problems for that stuff.