Asmall object with an initial temperature of 135 degrees fahrenheit is dropped into a tub with a temperature of 60 degrees fahrenheit. the function f(t)=ce(−kt)+60 represents the situation, where t is time in minutes, c is a constant, and k is a constant. after 6 minutes the object has a temperature of 85 degrees. what is the approximate value of k?

0.1831 s⁻¹

Explanation:

The function represents the temperature of the object at a certain time. Because there's a difference in temperature between the object and the tube, heat must flow from the object, and they will achieve thermal equilibrium.

At the beginning, t = 0, the temperature is 135°F, thus:

135 = C + 60

C = 75°F

After 6 minutes, t = 6, the temperature is 85°F, thus:

-6k = -1.0986

k = 0.1831 s⁻¹

first one is the correct answer