To find out the temperature at an altitude of 7,000 feet given a surface temperature of 80 degrees Fahrenheit and an environmental lapse rate of 3.5°F per 1,000 feet, follow these steps:
1. Understand the lapse rate: The lapse rate indicates the rate of temperature decrease with an increase in altitude. Here, it is given as 3.5°F per 1,000 feet.
2. Determine altitude: The problem states an altitude of 7,000 feet.
3. Calculate the temperature drop:
- Divide the altitude (7,000 feet) by 1,000 to find how many units of 1,000 feet are in 7,000 feet:
\( 7,000 \, \text{feet} \div 1,000 = 7 \, \text{units} \).
- Multiply this number by the lapse rate (3.5°F per 1,000 feet) to find the total temperature drop:
\( 7 \, \text{units} \times 3.5 \, \text{°F/unit} = 24.5 \, \text{°F} \).
4. Calculate the final temperature:
- Subtract the temperature drop from the initial temperature:
\( 80 \, \text{°F} - 24.5 \, \text{°F} = 55.5 \, \text{°F} \).
Thus, the temperature at 7,000 feet is [tex]\(\boxed{55.5 \, \text{°F}}\)[/tex].
