4. A 3 kg copper part, initially at 500 K, is plunged into a tank containing 5 kg of liquid water, initially at 300 K. The copper part and water can be modeled as incompressible with specific heats 0.385 kJ/kg-K and 4.2 kJ/kg-K, respectively. The heat transfer between the tank and the surroundings is negligible. Determine a) The final equilibrium temperature of the copper part and water, in K b) The amount of entropy produced within the tank, in kJ/K