I have a mid 2009 15" MBP, my girlfriend has a mid 2010 15" MBP. We were messing around with our settings and noticed under System Preferences>Trackpad>2 Fingers, mine says "Scrolling with inertia" and her's says "Scrolling with momentum". Both of our machines are completely up to date, and everything works the same - just curious what the difference is. Any ideas? Thanks.