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iogann1982 [59]
4 years ago
12

Ear "popping" is an unpleasant phenomenon sometimes experienced when a change in pressure occurs, for example in a

Engineering
1 answer:
lara31 [8.8K]4 years ago
7 0

Answer:

a) dh_HG = 6.72 mm

b) dz' = 173 m @8000 m

Explanation:

Given:

Original height h_o = 3000 m

Descent = 100 m

Find:

what is the pressure change that your ears "pop" at, in millimeters of mercury?

If the airplane now rises to  8000 m and again begins descending, how far will the airplane descend before your ears "pop" again?

Solution:

- Assuming density of air remains constant from 3000 m to 2900 m. From Table A3:

                 p_air = 0.7423*p_SL = 0.7423*1.225 kg/m^3

                 p_air = 0.909 kg/m^3

- Manometer equation for air and mercury are as follows:

                dP = -p_air*g*descent                        dP = -p_HG*g*dh_HG

Combine the pressures dP:

               dh_HG = (p_air / p_HG)*descent

               dh_HG = 0.909*100 / 13.55*999

              dh_HG = 6.72 mm

- Assuming density of air remains constant from 8000 m to 7900 m. From Table A3:

                   p_air = 0.4292*p_SL = 0.4292*1.225 kg/m^3

                   p_air = 0.526 kg/m^3

- Manometer equation for air are as follows:

                       @8000m                                 @3000m

                dP = -p'_air*g*dz'                       dP = -p_air*g*dz

                                           

                                     dz' = p_air / p'_air * dz

                                     dz' = 0.909 / 0.526 * 100

                                     dz' = 173 m

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There are two halves of scarcity that have plagued us ever since we first set foot on this Earth:

Limited resources.
Unlimited wants.
The Economics of Seinfeld says the following regarding the term:

“Unlimited wants essentially mean that people never get enough, that there is always something else that they would like to have.”

“When combined with limited resources, unlimited wants result in the fundamental problem of scarcity.”

Unlimited wants – limited resources

What we want and need has no limit, i.e., it is infinite. However, what we can afford is finite, i.e., it has a limit. This is a basic condition of human existence.

We are never completely satisfied with everything we consume. We consume a variety of goods and services, but they are never enough.

In other words, there is always something else that I, you, or anybody else would want or need.

The term applies to all socioeconomic groups. Low-income groups have limited resources, and their wants always exceed those resources. However, the same happens with middle-income and upper-income groups. They never feel they have enough.

The reason is a very simple one. Every income group’s resources are finite. However, unlimited want is a feature of every human.

Put simply; our wants and needs are infinite, but our wealth is not.

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In other words, markets fores, i.e., the forces of supply and demand, in a free market economy, determine prices.

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