I often coach casting (FFF) and when talking to novices and encouraging them to let the rod do the work - and thereby NOT use a throwing motion (bent wrist, arm outstetched) to propel the line - I point out that with a 9ft rod in a proper cast the rod tip should travel about 12ft in a straight line.
If that movement takes 1/10 second, the line is moving @ 80mph. Or maybe it is 1/5 second and the line is moving 40mph.
In either case it is easy to make the point that the line will go out if it is moving that fast, and more 'oomph' is not needed.
However I would like to be accurate and know the speed of a normal stroke for about 40' of line and Google has not provided a ready answer. Any ideas? Thanks.