Friction is a force between two surfaces that are sliding, or trying to slide, across each other.
Friction always slows a moving object down. Air resistance is a type of friction.
This section includes:
This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.