I was given a question,
"A thermos bottle containing milk is shaken vigorously. Consider the milk as the system.
(a) Will the temperature rise as a result of the shaking?
(b) has heat been added to the system?
(c) Has work been done on the system?
(d) Has the system's internal energy changed?".
I know that the shaking, which can be viewed more simply as stirring, does increase the temperature of the system, and work has been done on the system, but does shaking/stirring add heat $Q$? If yes, could someone explain how? And how would that effect the internal energy (U)?