Chapter 10, Problem 5RQ

1. 5. You enjoy drinking coffee but are particular about the temperature (T) of your coffee. If the temperature is greater than or equal to 70 degrees Celsius [⁰C], the coffee is too hot to drink; less than or equal to 45°C is too cold by your standards. Your coffee pot produces coffee at the initial temperature (T₀). The cooling of your coffee can be modeled by the following equation, where time (t) and the cooling factor (k) are in units per second:

   T = T₀e^–kt

   1. a. At the top of the worksheet, create an area where the user can modify four properties of the coffee. For a sample test case, enter the following data.
      • Initial temperature (T₀); for the initial problem, set to 80°C.
      • Cooling factor (k); set to 0.001 per second (s^–1].
      • Temperature above which coffee is “Too Hot” to drink (T_hot); set to 70°C.
      • Temperature below which coffee is “Too Cold” to drink (T_cold); set to 45°C.
   2. b. ^{Create a temperature profile for the coffee:}
      • In column A, generate a time range of 0–300 seconds, in 15-second intervals.
      • In column B, generate the temperature of the coffee, using the equation given and the input parameters set by the user (T₀ and k).
   3. c. In column B, the temperature values should appear on a red background if the coffee is too hot to drink, and a blue background if it is too cold using conditional formatting.
2. d. In column C, create a warning next to each temperature that says “Do Not Drink” if the calculated temperature in column B is too hot or too cold in comparison with the temperature values the user enters.

A sample worksheet is shown here for the test case described in part (a).

Coffee Parameters
Initial Temperature(T0)	80	[°C]
Cooling Factor(k)	0.001	[1/s]
Too Hot Temperature(Thot)	70	[°C]
Too Cold Temperature (Tcold)	45	[°C]

Time[S]	Temperature [deg C]	Warning!
0	80	Do not Drink
15	79	Do not Drink
30	78	Do not Drink
45	76	Do not Drink
60	75	Do not Drink
75	74	Do not Drink
90	73	Do not Drink
105	72	Do not Drink
120	71	Do not Drink
135	70
150	69
165	68
180	67