06-30-2019, 01:48 PM
The Hyperphysics website is getting a bit dated in the presentation (and that is not a bad thing in and of itself) but such a wonderful resource for physics and astronomy concepts. Thanks Georgia State!
http://hyperphysics.phy-astr.gsu.edu/hbase/hframe.html
http://hyperphysics.phy-astr.gsu.edu/hbase/hframe.html