Pressure

Question 1

How do you define pressure? What is the unit of measurement?

Answer 1

Pressure = force

1N/M2 = 1 Pascal (Pa). 100Pa = hPa

Standard atmospheric pressure = 1013.25hPa (101,325pa)

Question 2

Why does atmospheric pressure decrease non-linearly with altitude?

Answer 2

Atmosphere is compressible downwards. There is 500km of atmosphere pressing down on the earth. Therefore the distribution of air molecules is much denser nearer the surface.

The greatest noticeable change is pressure is nearer the surface, getting increasingly less noticeable with altitude.

Question 3

What is the barometric lapse rate at MSL?

Answer 3

At MSL: 27ft/hPa

Question 4

What is a pressure altitude?

Answer 4

the altitude measured when we use 1013 as our reference, at which the ISA pressures are true.

Question 5

What is the standard pressure at 10,000 feet?

Answer 5

700 hPa

Question 6

What is the standard pressure at 18,000 feet? And the barometric lapse rate?

Answer 6

500 hPa

50ft/hPa

Question 7

What is the standard pressure at 30,000?

Answer 7

300hPa

Question 8

What is the standard pressure at 40,000 feet?

And the new barometric lapse rate?

Answer 8

200hPa

110ft/hPa

Question 9

What is the standard pressure at 43,000 feet?

Answer 9

150hPa

Question 10

What is the standard pressue at 5000 feet?

Answer 10

850 hPa