Minor comment on notation: The symbols u' and u'' are used but not defined. Of course, these refer to the time derivatives of u, which is defined. But elsewhere on the page time derivatives are written explicitly as
If you agree with the assessment, please remove {{Physics}}'s auto=yes parameter from this talk page.
If you disagree with the assessment, please change it by editing the class parameter of the {{Physics}} template, removing {{Physics}}'s auto=yes parameter from this talk page, and removing the stub template from the article.