Milk is flowing through a heat exchanger at a rate of 2000kg/h. The heat exchanger supplies 11,600kJ/h. The outlet temperature of the product is 95C. Determine the inlet temperature of the milk. The product specific heat is 3.9kJ/(kg C)

answer : a model is often used to explain and make things easier to understand when any scientific topic needs to be demonstrated and explained.

as in this case where a scientist wants to use a model to present the results of his detailed scientific investigation. he should do it as it will him to make the audience understand the concept in a much better way. also, it can be changed according to new scientific understandings.