nˈɛɡətˌɪv wˈɜːk hˈæpənz wɛn ɐn ˈæktʃuːˌeɪɾɚɹ ɐplˈaɪz fˈoːɹs ˈɑːpəzˌɪt fɹʌm ɪts mˈoʊʃən ænd ɐbsˈoːɹbz ˈɛnɚdʒi fɹʌmðə sˈɪstəm ˌæksɪdˈɛntəli.
Negative work happens when an actuator applies force opposite from its motion and absorbs energy from the system accidentally.