The last chapter of most introductory textbooks on STATICS introduces VIRTUAL WORK. It is rarely taught (I studied the syllabi of colleagues). I understand the Principle of Virtual Work, having researched and studied the Calculus of Variations, Hamilton's Principle, the Lagrangian and related items. But I am trying to give myself a short, concise justification for why VIRTUAL WORK... works, but WITHOUT the higher math justifications. For example, the opening chapter of one text on Statics states: "The principle of virtual work was pioneered by Bernoulli. It provides an alternative methof for solving equilibrium problems..... The PVW states that if a system exists in equilibrium, then the sum of all the work done by virtual displacments is 0" Well (and please forgive me): whoppie-do, so it does. Like magic, it works. Well, can someone justify why it works WITHOUT recourse to the higher mathematics I mentioned above? I am hoping for a concise justification on why it should work... without the math.