Dynarnics On the basis of D'Alembert's Principle and of the Theorem of Virtual Displacements in this chapter the general equation of dynamics and the Lagranges equations of the second kind (abbreviated as Lagrange's equations)is deduced. The general equation of dynamics and the Lagrange's equations are effective means to study dynamical problems. They provide very simple, direct and standard ways to solve dynamical problems of unfree systems of particles.3 On the basis of D‘Alembert’s Principle and of the Theorem of Virtual Displacements in this chapter the general equation of dynamics and the Lagrange's equations of the second kind (abbreviated as Lagrange's equations) is deduced. The general equation of dynamics and the Lagrange's equations are effective means to study dynamical problems. They provide very simple, direct and standard ways to solve dynamical problems of unfree systems of particles