The figure shows the pV diagram for a certain thermodynamic process. In this process. 1510 J of heat flows into a system. and at the same time the system expands against a constant extemal pressure of 4 x 104 Pa. If the volume of the system increases from 0.020 m3 to 6.10-2 m3. Calculate the change in internal (thermal) energy of the system. If the internal (thermal) energy change is nonzero. be sure to indicate whether this energy change is positive or negative.