491 A large cast iron container (k = 52 W/mK and = 1.70 105 m2 /s) with 4-cm-thick walls is initially at a uniform temperature of 0C and is filled with ice at 0C. Now the outer surfaces of the container are exposed to hot water at 55C with a very large heat transfer coefficient. Determine how long it will be before the ice inside the container starts melting. Also,