I am (still) working on getting a good understanding of Lagrange multipliers. I understand their function in an optimization problem that is subject to some constraint.
For the specific case of equations of motion of a dynamic system (Newton-Euler equations), my teacher showed me that the mathematical multiplier can physically be interpreted as constraint force.
About this 'force', could someone explain/show to me
why it never does/cannot do work? (Wikipedia)
what happens when the constraint is redundant, i.e. already satisfied?