Chapter 1, Problem 1.72P

The roof of a car in a parking lot absorbs a solar radiant flux of $\text{8}00\text{ W}/{\text{m}}^{\text{2}}$ , and the underside is perfectly insulated. The convection coefficient between the roof andthe ambient air is $12{\text{W/m}}^{\text{2}}\cdot \text{K}$ .
(a) Neglecting radiation exchange with the surroundings,calculate the temperature of the roof under steady-state conditions if the ambient air temperature is 20°C.
(b) For the same ambient air temperature, calculatethe temperature of the roof if its surface emissivityis 0.8.
(c) The convection coefficient depends on airflow conditions over the roof, increasing with increasing airspeed. Compute and plot the roof temperature as afunction of hfor $2\le h\le 200{\text{W/m}}^{\text{2}}\cdot \text{K}$ .