College

A turkey at room temperature [tex](68^{\circ} F)[/tex] is placed into an oven at [tex]8 \, a.m.[/tex] when the oven temperature is [tex]325^{\circ} F[/tex]. According to Newton's Law of Heating, the temperature of the turkey will increase proportionally to the difference between the temperature of the turkey and the temperature of the oven.

The turkey reaches a temperature of approximately [tex]100^{\circ} F[/tex] after 2 hours. Find the value of [tex]k[/tex] to the nearest thousandth.

Using your value for [tex]k[/tex], determine the Fahrenheit temperature of the turkey to the nearest degree at 3 p.m.

Answer :

To solve this problem, we'll apply Newton's Law of Heating. According to this law, the rate of temperature change of an object is proportional to the difference between its current temperature and the surrounding temperature.

Here’s a step-by-step guide on how to find the value of [tex]\( k \)[/tex] and the temperature of the turkey at 3 p.m.:

### Step 1: Understand the Formula

The formula for Newton's Law of Heating is given by:

[tex]\[ T(t) = T_{\text{env}} + (T_{\text{initial}} - T_{\text{env}}) \times e^{-kt} \][/tex]

Where:
- [tex]\( T(t) \)[/tex] = Temperature of the turkey at time [tex]\( t \)[/tex]
- [tex]\( T_{\text{env}} \)[/tex] = Oven temperature, which is [tex]\( 325^\circ F \)[/tex]
- [tex]\( T_{\text{initial}} \)[/tex] = Initial turkey temperature, which is [tex]\( 68^\circ F \)[/tex]
- [tex]\( t \)[/tex] = Time in hours
- [tex]\( k \)[/tex] = Constant of proportionality

### Step 2: Use Given Data to Find [tex]\( k \)[/tex]

You know that after 2 hours, the turkey's temperature is [tex]\( 100^\circ F \)[/tex]. Plug these values into the formula:

[tex]\[ 100 = 325 + (68 - 325) \times e^{-k \times 2} \][/tex]

### Step 3: Calculate [tex]\( k \)[/tex]

Solve for [tex]\( k \)[/tex] in the equation above to determine the rate of heating.

The calculated value of [tex]\( k \)[/tex] is approximately [tex]\( 0.0665 \)[/tex].

### Step 4: Find the Turkey's Temperature at 3 p.m.

3 p.m. is 7 hours after 8 a.m., so [tex]\( t = 7 \)[/tex].

Using the formula:

[tex]\[ T(7) = 325 + (68 - 325) \times e^{-0.0665 \times 7} \][/tex]

### Step 5: Calculate the Temperature

The temperature of the turkey at 3 p.m. is approximately [tex]\( 163.64^\circ F \)[/tex].

So, the turkey reaches a temperature of about [tex]\( 163.64^\circ F \)[/tex] by 3 p.m.