Fe. Udwadia et al., EQUATIONS OF MOTION FOR CONSTRAINED MECHANICAL SYSTEMS AND THE EXTENDED DALEMBERT PRINCIPLE, Quarterly of applied mathematics, 55(2), 1997, pp. 321-331
Starting from the principle of virtual work, this paper states and est
ablishes an extended version of D'Alembert's Principle. Using this ext
ended principle and elementary linear algebra, it develops, from first
principles, the explicit equation of motion for constrained mechanica
l systems. The results are compared with the authors' previous results
. The approach points to new ways of extending these results.