4-36 A short, cylindrical aluminum bar [k = 200 W/(m °C) and x = 8.4 x 10-5 m²/s] of diameter D = 6 cm and height L = 3 cm is initially at a uniform temperature 7 = 175°C. Suddenly the surfaces are subjected to convective cooling with a heat transfer coefficient h = 250 W/(m² °C) into an ambient at T = 25°C. Calculate the center temperature To of the cylinder = 1 min after the start of the cooling. Answer: 93.3°C