Awall with wood studs has fiberglass insulation between the studs. the insulation has r = 21.1 and the wood r = 9.7 (usual units). the studs occupy 18% of the wall area. what is the overall r for the wall and studs? wall studs are usually placed 16 or 24 inches apart in a woodframed home. these wood pieces are called “two by fours” or 2” thick and 4” width. they are actually 1.5” by 3.5”. for the wall considered here with 18% stud coverage is the spacing 16 or 24 inches apart?

A2-m rigid tank initially contains saturated water vapor at 100 kpa. the tank is connected to a supply line through a valve. steam is flowing in the supply line at 600 kpa and 300 c. the valve is opened, and steam is allowed to enter the tank until the pressure in the tank reaches the line pressure, at which point the valve is closed. a thermometer placed in the tank indicates that the temperature at the final state is 200°c. determine (a) the mass of steam that has entered the tank (b) the amount of heat transfer.