4-118 A short brass cylinder (p = 8530 kg/m3,Cp = 0.389 kJ/kg-K, k = 110 W/m-K, and a = 3.39 x 10-5 m²/s) of diameter 4 cm and height 20 cm is initially at a uniform temperature of 150°C. The cylinder is now placed in atmospheric air at 20°C,where heat transfer takes place by convection with a heat transfer coefficient of 40 W/m².K.Calculate (a) the center temperature of the cylinder; (b) the center temperature of the top surface of the cylinder; and (c) the total heat transfer from the cylinder 15 min after the start of the cooling. Solve this problem using the analytical one-term approximation method.

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