A long 20-cm-diameter cylindrical shaft made of stainless steel 304 comes out of an oven at a uniform temperature of 600C. The shaft is then allowed to cool slowly in an environment chamber at 200C with an average heat transfer coefficient of h=80W/m2.C. The properties of stainless steel 304 are: thermal conductivity k=14.9W/mC, density =7900 kg/m3, specific heat Cp=477J/kgC. a) Determine the temperature at centre of the shaft 45min after the start of the cooling process. (4) b) Determine the temperature at 8cm from the centerline. (3) b) Determine the total energy per unit length of the shaft during this time period. (3)