Water at a rate of 45,500 kg/h is heated from 80 to 150\degc in a heat exchanger having two shell passes and eight tube passes with a total surface area of 925 m2. Hot exhaust gases having approximately the same thermophysical properties as air enter at 350\degc and exit at 175\degc. Determine the overall heat transfer coefficient.

Plot schematically the tensile stress versus strain curves for a typical thermoplastic material at a temperature below its glass transition temperature (tg and at a temperature above its tg, respectively. do the same for a typical thermosetting material. list in a table any differences or similarities between the two materials at t> tg and t < tg, respectively, and relate them to the structures of the two types of polymers