In Yosemite it was possible to enable scrolling without inertia in accessibility settings:
However, in El Capitan (10.11) this only works for some apps. Firefox scrolls without inertia, but most Apple apps (Mail, Preview, Calendar) disregard the setting and scroll with inertia. This is driving me crazy - anyone know how to completely disable inertia for all apps?
I've filed a bug report with Apple and received the following response:
This issue behaves as intended based on the following:
Inertia is now a feature.
We are now closing this bug report.
Great. It's not a bug, it's a feature! Then why does this setting even exist? I really hope they change their mind and re-implement it.