Ahole of diameter d = 0.25 m is drilled through the center of a solid block of square cross section with w = 1 m on a side. the hole is drilled along the length, l = 2 m, of the block, which has a thermal conductivity of k = 150 w/m ⋅ k. the four outer surfaces are exposed to ambient air, with t[infinity],2 = 25°c and h2 = 4 w/m2 ⋅ k, while hot oil flowing through the hole is characterized by t[infinity],1 = 300°c and h1 = 50 w/m2 ⋅ k. determine the corresponding heat rate and surface temperatures.