A perfectly stirred, constant-volume tank has two input streams, both consisting of the same liquid. The temperature and flow rate of each of the streams can vary with time. Derive a dynamic model of the process. Subsequently, make a "degrees of freedom" analysis assuming that both streams 1 and 2 come from upstream units (i. e., their flow rates and temperatures are known functions of time). Notes: wi denotes mass flow rate for stream i. Liquid properties are constant (not functions of temperature).