Question

A student brings a cup of hot (190° ) coffee to her evening Differential Equations course. Unfortunately, the classroom is 80° that day because the air conditioner is broken. Ms. Jensen opens the door and the classroom begins to cool at a constant rate of 10° per hour. The student is so absorbed in the class that she forgets about her coffee and it sits on her desk for 50 minutes as the classroom cools down. In this problem the proportionality constant for Newton’s law of cooling is ? = −2. What temperature is the student’s coffee after 50 minutes ( ≈ 0.83 hours)? Note that here the ambient temperature is not a constant, but a function ??(?) of time ?.

Answer 1