I found physics 2 waaayy easier and more fun than physics 1 (I'm at UW-Madison), but I think it really depends on your school/prof etc. I'm really not sure how you could end up needing physics 2 without physics 1, but I think it is plenty do-able. The course doesn't require much additive knowledge with the exception of waves and vectors as already mentioned. Best of luck if you go for it!