[Phys-L] Textbook Errors re Waterjet Levitation

[brian whatcott <betwys1@sbcglobal.net>]

You may have been asked what motivates the levitation by water jet of 
the kind shown here:
https://physics.stackexchange.com/questions/8947/how-does-the-water-jet-pack-work



Vera et al wrote in "Fire Technology" shown here:
https://link.springer.com/article/10.1007/s10694-018-0719-x

"we also showed that*the conceptual error of a backwards reaction force 
with a magnitude equal to the jet momentum flow rate is of widespread 
use in several physics textbooks* [5 
<https://link.springer.com/article/10.1007/s10694-018-0719-x#CR5>,6 
<https://link.springer.com/article/10.1007/s10694-018-0719-x#CR6>,7 
<https://link.springer.com/article/10.1007/s10694-018-0719-x#CR7>]."


1.
   5.
   Serway RA, Jewett JW (2009) Physics for scientists and engineers,
   8th edn. Brooks Cole, Belmont, p 264Google Scholar
   <http://scholar.google.com/scholar_lookup?title=Physics%20for%20scientists%20and%20engineers&author=RA.%20Serway&author=JW.%20Jewett&publication_year=2009>
2.
   6.
   Lewin W (2012) For the love of physics: from the end of the rainbow
   to the edge of time???a journey through the wonders of physics, 1st
   edn. Free Press, New YorkGoogle Scholar
   <http://scholar.google.com/scholar_lookup?title=For%20the%20love%20of%20physics%3A%20from%20the%20end%20of%20the%20rainbow%20to%20the%20edge%20of%20time%E2%80%94a%20journey%20through%20the%20wonders%20of%20physics&author=W.%20Lewin&publication_year=2012>
3.
   7.
   Sprott JC (2006) Physics demonstrations: a sourcebook for teachers
   of physics. University of Wisconsin Press, MadisonGoogle Scholar
   <https://scholar.google.com/scholar?q=Sprott%20JC%20%282006%29%20Physics%20demonstrations%3A%20a%20sourcebook%20for%20teachers%20of%20physics.%20University%20of%20Wisconsin%20Press%2C%20Madison>


It appears that the 'magic' has to do with the U-turn in the water flow...

Brian W