Sometimes textbooks gloss over the subtleties. If the free expansion is infinitesimally slow, I would agree. If it is sudden, I would not agree, for the reasons stated above.ZapperZ said:Not if no force is applied to cause the translation. Don't forget that work, by definition, is the sum of the applied force with the resulting translation. A simple translation alone is not a sufficient criteria to automatically indicate that work is done.
In any case, I thought the fact that adiabatic free expansion does no work is a "textbook" stuff.