<p>How is physics 7B without having taken 7A? I know 7A is a prerequisite and I am currently taking it right now, but I'm not doing so well. I really don't want to take 7A in the fall so I was planning on reversing it and taking 7B in the fall and 7A in the Spring. I think 7B has to do with magnetism, How much of 7A do I need for 7B?</p>