College Algebra & Trigonometry, 2018a

3.5. APPLICATIONS OF THE NEGATIVE EXPONENTIAL FUNCTION 187
8) A roasted turkey is taken from the oven when its temperature has reached
185 ◦ F and is placed on a table in a room where the temperature is 75 ◦ F.
a) If the temperature of the turkey is 150 ◦ F after 30 minutes, what is its temperature
after 45 minutes?
b) When will the turkey cool off to 100 ◦ F?
9) A kettle full of water is brought to a boil in a room with an ambient temperature
of 20 ◦ C. After 15 minutes, the temperature of the water has decreased from
100 ◦ Cto75 ◦ C. Find an equation using Newton’s Law of Cooling to represent to
temperature at time t. Find the temperature of the water after 25 minutes.
10) A cup of coffee with a temperature of 105 ◦ F is placed in a freezer with a
temperature of 0 ◦ F. After 5 minutes, the temperature of the coffee is 70 ◦ F. Find an
equation using Newton’s Law of Cooling to represent to temperature at time t.
What will the temperature be in 10 minutes?