A) 350 J
- The initial internal energy of the cup is
[tex]U_i = 230 J[/tex]
- The final internal energy of the cup is
[tex]U_f = 580 J[/tex]
According to the first law of thermodynamics:
[tex]U_f - U_i = Q+W[/tex]
where
Q is the heat absorbed by the system
W is the work done on the system
The work done on the system in this case is 0, so we can rewrite the equation as
[tex]U_f - U_i = Q[/tex]
And so we find the heat transferred
[tex]Q=580 J - 230 J=350 J[/tex]
B) IN the cup
Explanation:
in this situation, we see that the internal energy of the cup increases. The internal energy of an object/substance is proportional to its temperature, so it is a measure of the average kinetic energy of the molecules of the object/substance. Therefore, in this case, the temperature (and the energy of the molecules of the substance) has increased: this means that heat has been transferred INTO the system from the environment (the heat came from the sun).
