A1 m thick wall is made of concrete with a thermal conductivity of 1 w/m/k. there are temperature sensors on the wall's surface and buried within the wall 1 cm from each surface. one set of temperature sensors shows the surface at 30 °c and the subsurface at 32 °c, while the other shows the surface at 40 °c and the subsurface at 35 °c a. is the wall heating up or cooling down? b. what's the rate of change of thermal energy contained per unit area of wall? c. would your answer change if the wall were 0.5 m thick?

Amass of m 1.5 kg of steam is contained in a closed rigid container. initially the pressure and temperature of the steam are: p 1.5 mpa and t 240°c (superheated state), respectively. then the temperature drops to t2= 100°c as the result of heat transfer to the surroundings. determine: a) quality of the steam at the end of the process, b) heat transfer with the surroundings. for: p1.5 mpa and t 240°c: enthalpy of superheated vapour is 2900 kj/kg, specific volume of superheated vapour is 0. 1483 m/kg, while for t 100°c: enthalpy of saturated liquid water is 419kj/kg, specific volume of saturated liquid water is 0.001043m/kg, enthalpy of saturated vapour is 2676 kj/kg, specific volume of saturated vapour is 1.672 m/kg and pressure is 0.1 mpa.

Two technicians are discussing the intake air temperature (iat) sensor. technician a says that the computer uses the iat sensor as a backup to the engine coolant temperature (ect) sensor. technician b says that the powertrain control module (pcm) will subtract the calculated amount of fuel if the air measures hot. who is correct

Fluids at rest possess no flow energy. a)- true b)- false