The document contains two physics problems involving heat transfer calculations. The first problem involves calculating the required thickness of insulation needed to limit heat loss from a furnace wall to 1830 W/m^2, given the wall thickness, material properties, and inner and outer surface temperatures. The second problem involves calculating the time required for the temperature at a depth of 25.4 mm to reach 388.8 K as a slab of aluminum cools at its surface.