Possible Duplicate:
Creating a Free Body Diagram in TikZ
As teachers of our department (physics and chemistry) that we do not like books which are sold in bookstores of our subject, we decided to make our own book with LaTeX. We did one last year and it was quite successful for us and for the students themselves.
A part of the subject are inclined planes, so I'd like to know if there is any "easy" way to do them, because having to be operating in a paper apart the coordinates of the points of all figures of the drawings is a arduous and tedious task.
The visual examples would be like this. (Examples colors are irrelevant)

diaalso. – Jan 24 '13 at 23:55