A number of questions, particularly involving homework, often involve some basic engineering. In the US, the National Society of Professional Engineers (NSPE - www.nspe.org) has arranged for the publication of various reference manuals as part of the training for licensing exams. The manuals contain an overview of the particular engineering discipline, some basic theory, general information, tables and fundamental equations, and example problems. Mechanical Engineering Reference Manual (for the PE Exam) Michael R. Lindeburg Civil Engineering Reference Manual (for the PE Exam) Michael R. Lindeburg Electrical Engineering Reference Manual (for the Electrical and Computer PE Exam) John A. Camara, Raymond B. Yarbrough Chemical Engineering Reference Manual for the PE Exam Michael R. Lindeburg These can be found through on-line book stores. I suspect Engineering Societies in other nations offer similar texts.