Chapter 18, Problem 81PP

Warm winds called Chinooks (a Native-American term meaning “snow eaters”) sometimes sweep across the plains just east of the Rocky Mountains. These winds carry air from high in the mountains down to the plains rapidly enough that the air has no time to exchange heat with its surroundings (Fig. 18.24). On a particular Chinook day, temperature and pressure high in the Colorado Rockies are 60 kPa and 260 K (−13°C), respectively; the plain below is at 90 kPa.

FIGURE 18.24 Chinooks (Passage Problems 80-83)

As the air descends, its internal energy

1. a. increases.
2. b. decreases.
3. c. is unchanged.