Question

Density changes with altitude at a rate.

A. of 2kg/m3 per 1000 ft.
B. which changes with altitude.
C. which is constant until 11 km.

Answer 1

Air density decreases with increasing altitude, and this relationship is depicted in Figure A4, showing that at the top of Mount Everest, air density is significantly lower than at sea level.

Step-by-step explanation:

The question is regarding the changes in air density with altitude and how this relationship can be described. As a student seeking to understand this concept, it's important to know that air density decreases as altitude increases. This change, under constant temperature conditions, is approximately exponential. However, temperature variations with altitude can alter the rate of density decrease.

For example, looking at Figure A4, which illustrates the Altitude-Air Density Relationship, we see that air density declines as altitude rises. At sea level, air is denser, while at the summit of Mount Everest, which stands at about 8,828 meters above sea level, the air density is significantly lower at 0.023 kilograms per cubic meter. This reduction in air density is why supplemental oxygen is often required by mountain climbers upon reaching high altitudes.

In summary, air density changes with altitude, with the density being higher at lower altitudes and gradually becoming less dense as one ascends to higher altitudes. This fact is important for various applications, including aviation, meteorology, and mountain climbing.

Answer 2

Density changes with altitude at a rate of A. 2 kg/m³ per 1000 ft.

Step-by-step explanation:

The correct choice is A, as the rate at which density changes with altitude is often expressed as a certain amount per unit change in altitude. The standard atmospheric lapse rate is approximately 2 kg/m³ per 1000 feet. This means that, on average, for every 1000 feet increase in altitude, the density of the atmosphere decreases by about 2 kg/m³.

The relationship between density and altitude is a critical concept in atmospheric science. The decrease in density with altitude is primarily due to the reduction in air pressure and temperature with increasing height. As altitude increases, the pressure and temperature of the atmosphere decrease, leading to a decrease in the number of air molecules in a given volume, thus reducing density.

Understanding the rate of change in density with altitude is essential in fields such as meteorology and aviation. Pilots and meteorologists use this knowledge to assess atmospheric conditions at different altitudes, influencing factors like aircraft performance, weather patterns, and atmospheric stability. The standard lapse rate provides a reference for the average change in density, allowing for more accurate predictions and calculations in these fields.