Chapter 4, Problem 14P

A brick of $203\times 102\times 57\text{ mm}$ in dimension is being burned in a kiln to 1100°C and then allowed to cool in a room with ambient air temperature of 30°C and convection heat transfer coefficient of 5 W/m² K. If the brick has properties of ${\text{p = 1920 kg/m}}^{\text{3}},cp=79\text{ J/kg}\text{.K and k = 0}\text{.90 W/m}\text{.K,}$, and k 0.90 W/m.K, determine the time required to cool the brick to a temperature difference of 5°C from the ambient air temperature.