Answer:
1500 J
Explanation:
We can solve the problem by using the first law of thermodynamics:
[tex]U_f - U_i = Q-W[/tex]
where
Uf is the final internal energy
Ui is the initial internal energy
Q is the heat absorbed by the system
W is the work done by the system
In this problem, we have:
Ui = 2000 J
Q = 1000 J
W = 500 J
Substituting into the equation above, we find:
[tex]U_i =U_f - Q+W=2000 J-1000 J+500 J=1500 J[/tex]