Problem 2 (25 points): A steel ball of 5 cm diameter at a temperature of 45ðC is suddenly placed in a gas environment of controlled temperature r = -10ðC. The heat transfer coefficient from the steel ball to the environment is h = 10 W/mðC. The properties of steel are: k = 45 W/mðC, p = 7800 kg/mó, and Cp = 460 J/kgðC. Neglect temperature change over the volume of the ball. Determine: a) How long will it take for the ball to reach a temperature of 150ðC? b) What would be the temperature of the ball after 40 minutes?