8.1 physics of the atmosphere

Question 1

Gases and Liquids are known as

Answer 1

Fluids

Question 2

what makes up our atmosphere

Answer 2

21 % oxygen
78 % nitrogen
1 % other gases

Question 3

what happens to air as altitude increases

Answer 3

composition remains the same.
but the pressure in the gas decreases

Question 4

the chemical composition of air starts to change when

Answer 4

at 60,000 ft

Question 5

usually oxygen accounts for approximately 0.2 ATM. what happpens if the local pressure is halved

Answer 5

the partial oxygen pressure only accounts for 0.1 ATM and vice versa

Question 6

compressibility allows air density to vary with what

Answer 6

pressure and temperature

Question 7

what is the average height of the atmosphere

Answer 7

760km

Question 8

exosphere extends to around

Answer 8

10,000km

Question 9

the atmosphere is divided into 5 main regions what are they

Answer 9

• Troposphere
• Stratosphere
• Mesosphere
• Thermosphere
• Exosphere

Question 10

the troposphere starts where and extends how far

Answer 10

earth’s surface 8-14.5 km (5 - 9 miles)

Question 11

what is the densest layer of the atmosphere

Answer 11

troposhere

Question 12

where do most modern jet aircraft cruise and why

Answer 12

tropopause , because the air is thinner which means less drag and higher fuel efficiency. also above most of the weather reducing turbulence

Question 13

the tropopause is how far from the equatorial and polar regions

Answer 13

17km and 9km

Question 14

the tropopause is also known as what

Answer 14

isothermal layer

Question 15

stratosphere starts where and extends how far

Answer 15

just above troposphere and extends 50km it also contains the protective Ozone layer

Question 16

temp in the stratosphere is usually about

Answer 16

-56.5 c

Question 17

aircraft flight is highly influenced by what

Answer 17

pressure (P)
temperature (T)
density (p)
humidity (“relative humidity”)

Question 18

formula for atmospheric Pressure is

Answer 18

P = F/A force / surface area

Question 19

the unit of pressure is pascal (Pa) which is equivalent to what

Answer 19

newton of force per metre squared area

N/m2

Question 20

static pressure =

Answer 20

P = p x g x h atmos density x gravitational field strength x height of atmos

Question 21

barometers measure what

Answer 21

absolute pressure

Question 22

what is used on aircraft to measure absolute pressure

Answer 22

aneroid capsules

Question 23

SI unit for temperature is

Answer 23

degrees celsius

Question 24

as altitude increases.. pressure and density

Answer 24

decrease

Question 24

the actual atmospheric temperature is very often expressed as what

Answer 24

outside air temperature (OAT)

Question 24

equation for density is

Answer 24

p = m/V density = mass/unit volume

Question 25

relative humidity is expressed as a

Answer 25

% percentage

Question 26

as humidity increases, the air density…

Answer 26

decreases

Question 27

what affects air density

Answer 27

pressure, temperature and humidity

Question 28

humidity is greatly affected by what

Answer 28

temperature

Question 29

dynamic pressure acts only in which direction

Answer 29

direction of the airflow

Question 30

dynamic pressure is denoted by what letter

Answer 30

q and is often called “q pressure”

Question 31

ISA is what

Answer 31

international standard atmosphere

Question 32

the isa values at sea level are

Answer 32

pressure 1013.25hPa
density 1.225 kg/m3
temperature 288.15 k or 15 degrees c

Question 33

air temperature decreases with increased altitude at a linear rate within the troposphere

Answer 33

.

Question 34

work =

Answer 34

force x distance N x m measured in newton metres

Question 35

acceleration =

Answer 35

change of speed/ time taken for change
V2 - V1 / time

Question 36

power =

Answer 36

work/ time or. force x distance/time

Question 37

is the speed of sound higher or lower at high altitudes

Answer 37

lower because the temperature is lower

Question 38

A barometer measures what

Answer 38

Absolute pressure

Question 39

What is the standard altitude for the tropopause

Answer 39

36,000 ft (11 km)