Two blocks of different temperatures are brought together.

Block A is a 360-kg block is made of Material X which has temperature dependent specific heat. Its initial temperature is T_A = 200° C. Block B is a 1000-kg iron block with an initial temperature T_B = 27° C. The specific heat of Material X in the range of interest is c_A = T*0.64 J/(kg K²) and the specific heat of iron is c_B = 452 J/(kg K).

We bring the two blocks together and wait for them to reach a common equilibrium temperature T_f. If we assume that the two block system does not lose energy to the environment, then what is the change in entropy of the two block system?

0^oC = 273.15 K

ΔS = J/K