A roast turkey is taken from an oven when its temperature has reached 185°F and is placed on a table in a room where the temperature is 75°F.
If the temperature of the turkey is 150°F after half an hour, what is the temperature after 35 minutes?
Since the room temperature is 75°F, Newton's Law of Cooling says that
dT/dt = k(T - 75)
Separating this gives us
dT / (T - 75) = k dt
Integrating both sides gives us ln|T - 75| = kt + C
This becomes T = 75 + e^(kt + C)
We now know that T = 75 + e^(kt + C) = 75 + Ke^(kt)
Since T(0) = 185, then K = 110
We have T = 75 + 110e^(kt)
Since the temperature after 30 minutes is 150°F, then e^(30k) = 15/22
So, k = (1/30)ln(15/22)
Since T = 75 + 110e^((1/30)(ln(15/22))t), we have the following. (Round your answer to the nearest whole number.)
T(35) =
When will the turkey have cooled to 95°F?
We must solve 95 = 75 + 110e^((1/30)(ln(15/22))t)
Now, we have the following. (Round your final answer to the nearest whole number.)
(1/30)(ln(15/22))t =
t =