Don't worry, no you didn't say the physics were bad I know. But take MadCat's suggestion because earlier on people were scratching their heads since some people could slide around all day and some people couldn't save a slide worth a turd. It turns out that there are a few things in the AC and video card settings that make a massive difference for some reason in AC (never saw these issues in any other sim but what the hell - the solutions make a massive difference in AC).
Flip back some pages in this very thread and there's a link PMD (EDIT: the other Phil) posted to an AC thread explaining all the things you need to change and why, and there's a bunch of information in this thread as well if you look back. If I wasn't such a lazy SOB I'd go back and link you the pages but alas...