AN INTRODUCTION TO LAGRANGE EQUATIONS Professor

This paper is intended as a minimal introduction to the application of Lagrange equations to the task of finding the equations of motion of a system of rigid bodies. A much more thorough and rigorous treatment is given in the text “Fundamentals of Applied Dynamics” by Prof. James H. Williams, Jr., published in 1996 by John Wiley and Sons. In particular the treatment given here to the evaluation of non-conservative external forces is simple and pragmatic. It will suffice for most of the applications at the level of an undergraduate course in engineering dynamics. Deeper understanding requires more work and the reader is referred to the Williams text. In writing this summary I have borrowed liberally from the Williams text and also from a previous subject handout, prepared by Prof. Sanjay Sarma of the Mechanical Engineering Department of MIT.