Carbon steel balls (rho = 7833 kg/m3, k = 54 w/m·°c, cp = 0.465 kj/kg·°c, and α = 1.474*10-6 m2 /s) 8 mm in diameter are annealed by heating them first to 900°c in a furnace and then allowing them to cool slowly to 100°c in ambient air at 35°c. if the average heat transfer coefficient is 75 w/m2 ·°c, determine how long the annealing process will take. if 2500 balls are to be annealed per hour, determine the total rate of heat transfer from the balls to the ambient.