Answer Happy

Problem 4 (20 Points) Semi-infinite solid 4. A tile-iron roof consists of a massive plate maintained at 150 °C by an embedded electrical heater. The iron is placed in contact with to soften the adhesive, allowing the tile to be easily lifted from the subflooring. The adhesive will soften sufficiently if heated above 50 °C for at least two minutes, but its temperature should not exceed 120 °C to avoid deterioration of the adhesive. Assume the tile and subfloor to have an initial temperature of 25 °C and to have equivalent thermophysical properties of: k-0.15 W/(m K); pcp=1.5 × 106 J/(m²K) Ts = 150 °C - Tile, 4 mm thick - Subflooring (a) How long will it take a worker using the tile iron to lift a tile? Will the adhesive temperature exceed 120 °C? (b) If the tile iron has a square surface area 254 mm to the side, how much energy has been removed from it during the time it has taken to lift the tile?