Iron balls having a diameter of 1.2 cm are to be quenched in water at a rate of 800 per minute. The balls leave the oven at a uniform temperature of 900 degrees * C and are exposed to air at for a...

Iron balls having a diameter of 1.2 cm are to be quenched in water at a rate of 800 per minute. The balls leave the oven at a uniform temperature of 900 degrees * C and are exposed to air at for a while before they are dropped into the water. If the temperature of the balls drops to 850 degrees * C prior to quenching, determine the rate of heat transfer from the balls to the air 25 degrees * C