
85
© 2010 Taylor & Francis Group, LLC
Lagrangian Formulation
of Mechanics
Descriptions of Motion in
Configuration Space
We have gained considerable experience in setting up Newton’s equations of motion in a variety of
problems. If the system is not subject to external constraints, the equations of motion are usually easy
to set up in Cartesian coordinates. If either the system is subject to external constraints or Cartesian
coordinates are not used, then the equations of motion may be difcult to solve or even to formulate.
Lagrange found a way to circumvent this problem by the use of generalized coordinates q
i
(to be
dened soon). In terms of these ...