Chapter 5, Problem 5.87P

A tile-iron consists of a massive plate maintained at $150°\text{C}$ by an embedded electrical heater. The iron is placed in contact with a tile to soften the adhesive, allowing the tile to be easily lifted from thesubflooring. The adhesive will soften sufficiently if heated above $50°\text{C}$ for at least 2 min, but its temperature should not exceed to avoid deterioration of the adhesive. Assume the tile and subfloor to have an initial temperature of $25°\text{C}$ and to have equivalent thermophysical properties of $k=0.15\text{W/m}\cdot \text{K}$ and $\rho c_p=1.5\times {10}^6{\text{J/m}}^{\text{3}}\cdot \text{K}\text{.}$

1. How long will it take a worker using the tile-iron to lift a tile? Will the adhesive temperature exceed $120°\text{C?}$
2. 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?