8.1 Physics Of The Atmosphere

Question 1

What is the unit of mass?

Answer 1

Kg

Question 2

What is the SI system?

Answer 2

It is based on the metric system and must be used as law throughout the world

Question 3

What is the definition of 1kg of mass?

Answer 3

The volume of one litre of pure water at 4°C

Question 4

What is the unit of length?

Answer 4

Metre (m)

Question 5

What is the unit of time?

Answer 5

Second (s)

Question 6

What is the unit of temperature?

Answer 6

Kelvin (K)

Question 7

What is the acceleration due to gravity?

Answer 7

9.8 m/s^2

Question 8

What are the 4 fundamental units of aerodynamics?

Answer 8

Mass, temperature, length and time

Question 9

What is weight measured in?

Answer 9

Newton’s (N)

Question 10

What is work?

Answer 10

Force multiplied by the distance (measured in Joules (J))

Question 11

What is power measured in?

Answer 11

Watts (same as Newton metres per second)

Question 12

What is the symbol for static pressure?

Answer 12

A small “p”

Question 13

What is the symbol for dynamic pressure?

Answer 13

Small letter “q”

Question 14

What is static pressure?

Answer 14

The pressure acts in all directions

- measured in N/m^2

Question 15

What is dynamic pressure?

Answer 15

Pressure that acts only in one direction

- measured in Bar

Question 16

What is 1 bar equal to?

Answer 16

100,000 pascal (Pa)

- deca-Newtons per square centimetre

Question 17

What is the speed of sound denoted by?

Answer 17

Small letter “a”

Measured in m/s

Question 18

What would a Mach number of 1 denote?

Answer 18

The aircraft is travelling at the speed of sound

Question 19

How is the Mach number calculated?

Answer 19

speed of the aircraft
—————————
speed of sound

Question 20

What is the pressure wave created as an aircraft travels at the speed of sound called?

Answer 20

The shock wave

Question 21

What are the three sound regions?

Answer 21

• subsonic
• transonic
• supersonic

Question 22

What is the critical Mach number?

Answer 22

The maximum speed before the formation of shock waves

Question 23

What are the two distances above the earth of the tropopause?

Answer 23

Equator = 16 kilometres
Poles = 8 kilometres

Question 24

What are the three parts of the atmosphere?

Answer 24

• Stratosphere
• Tropopause
• Troposphere

Question 25

Who introduced the standard atmosphere?

Answer 25

The ICAO

Question 26

What is the standard for the tropopause according to the ISA?

Answer 26

11 kilometres

Question 27

What does ISA stand for?

Answer 27

International Standard Atmosphere

Question 28

Under standard conditions, what does the temperature decrease by with altitude?

Answer 28

6.5 degrees per kilometre

Question 29

What is the standard temperature of the tropopause?

Answer 29

• 56.5 degrees Celsius

Question 30

Where in the atmosphere is there no temperature change?

Answer 30

The stratosphere

Question 31

Which level of the atmosphere contains the weather conditions such as clouds and rain?

Answer 31

The troposphere

Question 32

What is the equation for speed?

Answer 32

Speed = distance
————
time

Question 33

What is the equation for acceleration?

Answer 33

Acceleration = change in velocity
————————
time taken

Question 34

What happens to the weight of an object if it is subject to a constant velocity?

Answer 34

There is no change to the weight

Question 35

What happens to the weight of an object if it is subject to acceleration?

Answer 35

The weight of the object increases due to the added force

Question 36

What is the formula for dynamic pressure?

Answer 36

Pressure = 1/2 P V^2

Question 37

What is the formula for static pressure?

Answer 37

P = Pgh

Question 38

What is the temperature, pressure and density at standard sea level?

Answer 38

Temp: 288K
Pressure: 1013 hecto-Pa
Density: 1.225 kg/m^3