Physics C is a calculus based physics course so you would be in a disadvantage, but you could use sources such as khan academy or other websites or books to learn calculus. I highly recommend reading the book- No bullshit guide to math and physics by Ivan Savov, this book goes over the...
I would generally spend 1 or 2 hours on a problem for a time limit because I don't want to over stress so I recommend you do the same. I believe that seeing how others solve problems doesn't limit your creativity but just allows you to see a problem in a different point of view. And for the...
I would recommend the book No Bullshit Guide to Math and Physics by Ivan Savov. It's a great book, it teaches high school math, physics, and calculus very well
A good book in astrophysics I enjoyed was the black hole war by Leonard Susskind it talks about how quantum mechanics helped with solving the question if black holes do or do not release information and it only contains one simple equation that is only talked about briefly