Awatermelon initially at 35": is to be cooled by dropping it into a lake at 15 =c. afterd h and 40 min of cooling, the centertemperature of watermelon is measured to be 20°c. treating the watermelon as a 20-cm-diameter sphere and using theproperties k= 0.618 w/m-k, a = 0.15 x 10—6 m2/s. p = 995 kg/m3. and cp: 4.18 kj/kg-k, determine the average heattransfer coefficient and the surface temperature of watermelon at the end of the cooling period.

Steel is coated with a thin layer of ceramic to protect against corrosion. what do you expect to happen to the coating when the temperature of the steel is increased significantly? explain.

For the closed feedwater heater below, feedwater enters state 3 at a pressure of 2000 psia and temperature of 420 °f at a rate of ix10 ibhr. the feedwat extracted steam enters state 1 at a pressure of 1000 psia and enthalpy of 1500 btu/lbm. the extracted er leaves at an enthalpy of 528.7 btu/lbm steam leaves as a saturated liquid. (16) a) determine the mass flow rate of the extraction steam used to heat the feedwater (10) b) determine the terminal temperature difference of the closed feedwater heater

Water at 55c flows across a flat plate whose surface temperature is held constant at 95c. if the temperature gradient at the plate's surface for a given value of x is 18 c/mm, find a) local heat transfer coefficient. b) heat flux