title_body: What software is used by the publishing companies to create diagrams in the introductory physics textbooks? What software is used to create free body diagrams, inclines, springs and so on in the introductory physics textbooks ?
  
  I know Adobe, Luxology, and many others could, but I am more interested in software with ready made objects, that could still create good looking diagrams with less effort. Most of the textbooks have 100s of such diagrams that are kind of good looking.
  
  Similar to http://lpsa.swarthmore.edu/Systems/MechTranslating/TransMechSysLeversPulleys.html
upvoted_answer: They are almost certainly done in TeX/LaTeX. TeX/LaTeX is not about "less effort", but exactness. It is a programming language for typesetting with a special emphasis on math and equations. TeX has a long history with the academic community in publishing. Explaining TeX and LaTeX is outside the scope of this forum (There is a TeX.stackexchange.com site). You can find some examples of how those types of diagrams are done here:
  
  http://www.texample.net/tikz/examples/tag/diagrams/