At a point on the airfoil in subsonic wind tunnel, the air pressure and temperature are 0.4 atm and 5°c, respectively. assuming the flow is isentropic. if the ambient air pressure is 1 atm, calculate the ambient air temperature and density

Awall of 0.5m thickness is to be constructed from a material which has average thermal conductivity of 1.4 w/mk. the wall is to be insulated with a material having an average thermal conductivity of 0.35 w/mk so that heat loss per square meter shall not exceed 1450 w. assume inner wall surface temperature of 1200°c and outer surface temperature of the insulation to be 15°c. calculate the thickness of insulation required.