A long steel bar has a rectangular cross-section ( 5 cm x 3 cm) and is initially at a uniform temperature of 25 C. It is placed in a furnace at a temperature of 1000 C. Find the temperature at the center of the bar after 15 minutes have elapsed. Assume:

Surface heat transfer coefficient = 100 W/m2K

k for steel = 30 W/mK

for steel = 0.050 m2/h