For AS students fresh from your IG success – AS is no harder, you just have to think and process information more clearly. A2 builds on AS success and is a formidable, serious qualification. You announce to the world that you’ve got a brain if you do well at A2. Have a look at a past paper (June 2016)
Similarly the MYP program should have prepared you well for IB studies, but it’s quite a jump from MYP. You have to learn quite a lot quite fast and examiners are looking for a high level of problem solving skill as well as a broad and quite in-depth understanding, also they penalise sloppy wording and poorly drawn diagrams and graphs. The usual tolerance is half a square either side, so bring a sharp pencil
The IB physics stuff for the new syllabus is here – there are lots of other places too. Take a look – this wiki has a lot of information.