### Home > CCA2 > Chapter 3 > Lesson 3.1.3 > Problem3-55

3-55.

If the cooling system in a light-water nuclear reactor is shut off, the temperature of the fuel rods will increase. The temperature of the fuel rods during the first hour could be modeled by the equation $T=680(1.0004)^t−655$, where t is the time in seconds, and T is the temperature of the fuel rods in degrees Fahrenheit. Average rate of change can be calculated by finding the slope between two points. Find the average rate at which the temperature changes for the first 30 minutes. Homework Help ✎

To find the average rate of temperature change for the first 30 minutes, find the points $(0,T)$ and $(30,T)$ using the equation that is given. Then find the slope between those points. Remember that t is the time in seconds.

$\frac{741.8 - 25}{1800-0} = 0.4^{\circ} \text{F/sec}$