Answer:
Decrease
Step-by-step explanation:
The mathematical relationship between heat, internal energy and work done by the system is given as:
△U = Q + W
where △U is the change in the internal energy
W is the workdone by the system
Q is the heat energy in the system
Since the workdone by the system is negative, when a system does work, there is a depletion in the amount of energy possessed by the system.
Due to this loss of energy by the system as a result of the workdone, the internal energy decreases.