To warm up some milk for a baby, a mother pours milk into a thin-walled glass whose diameter is 6 cm. the height of the milk in the glass is 8 cm. she then places the glass into a large pan filled with hot water at 75°c. the milk is stirred constantly, so that its temperature is uniform at all times. if the heat transfer coefficient between the water and the glass is 125 w/m2 · °c, determine how long it will take for the milk to warm up from 5°c to 40°c. assume the entire surface area of the cylinder container (including the top and bottom) is in thermal contact with the hot water. take the properties of the milk to be the same as those of water. can the milk in this case be treated as a lumped system? why?