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**As you can see from the very last line of my post, this whole post may come from the fact that I don't get sarcasm**

Hi, reading the above mentioned book I ran into the following footnote:

pag 77 said:Those scientist who claim that analytical mechanics is nothing but a mathematically different formulation of the laws of Newton must assume that Postulate A is deducible from the Newtonian laws of motion. The author is unable to see how this can be done. Certainly the third law of motion, "action equals reaction", is not wide enough to replace Postulate A

Postulate A was earlier stated as:

The virtual work of the forces of reaction is always zero for any virtual displacement which is in harmony with the given kinematic constraints

An alternative, but equal, version of Postulate A is given the page before

The principle of virtual workassets that the given mechanical system will be in equilibrium if, and only if, the total virtual work of all the impressed forces vanishes:

$$ {\delta w} = \sum_i^{n} \mathbf F_i \cdot \delta \mathbf R_i = 0$$

The importance of Postulate A is later reinforced:

This postulate is not restricted to the realm of statics. It applies equally to dynamics, when the principle of virtual work is suitably generalized by means of d'Alembert principle. Since all the fundamental variational principles of mechanics, the principles of Euler, Lagrange, Jacobi, Hamilton, are but alternative mathematical formulations of d'Alembert principle, Postulate A is actually theonlypostulate of analytical mechanics

Going back to the original question: do you think there is a way to deduce Postulate A from Newton's laws? Because I didn't understand if the author left it as an open question or if he was just being sarcastic.

Thanks

Ric