Long cylindrical steel rods (r = 7833 kg/m3 and cp = 0.465 kJ/kg C) of 10-cm

Question:

Long cylindrical steel rods (r = 7833 kg/m3 and cp = 0.465 kJ/kg • °C) of 10-cm diameter are heat-treated by drawing them at a velocity of 3 m/min through an oven maintained at 900°C. If the rods enter the oven at 30°C and leave at a mean temperature of 700°C, determine the rate of heat transfer to the rods in the oven.