This isn't the same as the unviolent "work", or if it is it's back in prehistory.

Pokorny list two different roots: first, *werg'-, (*wreg'- 'to work, to do, maske'; *werg'om, p.1168), whence English work, Greek (w)ergon. And second, *wreg- (*werg- 'to hit, strike, press, urge, thump, propel, impel', p.1181), whence Latin urgeo, English wreck, wreak, and irk (from Old Norse). Calvert Watkins, in the A-H IE roots appendix, suggests they are the same root, and that the second one is really a zero-grade of the first.

http://www.bartleby.com/61/roots/IE577.html