8.1 Physics Of The Atmosphere Flashcards Preview

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Flashcards in 8.1 Physics Of The Atmosphere Deck (38)
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1
Q

What is the unit of mass?

A

Kg

2
Q

What is the SI system?

A

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

3
Q

What is the definition of 1kg of mass?

A

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

4
Q

What is the unit of length?

A

Metre (m)

5
Q

What is the unit of time?

A

Second (s)

6
Q

What is the unit of temperature?

A

Kelvin (K)

7
Q

What is the acceleration due to gravity?

A

9.8 m/s^2

8
Q

What are the 4 fundamental units of aerodynamics?

A

Mass, temperature, length and time

9
Q

What is weight measured in?

A

Newton’s (N)

10
Q

What is work?

A

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

11
Q

What is power measured in?

A

Watts (same as Newton metres per second)

12
Q

What is the symbol for static pressure?

A

A small “p”

13
Q

What is the symbol for dynamic pressure?

A

Small letter “q”

14
Q

What is static pressure?

A

The pressure acts in all directions

- measured in N/m^2

15
Q

What is dynamic pressure?

A

Pressure that acts only in one direction

- measured in Bar

16
Q

What is 1 bar equal to?

A

100,000 pascal (Pa)

- deca-Newtons per square centimetre

17
Q

What is the speed of sound denoted by?

A

Small letter “a”

Measured in m/s

18
Q

What would a Mach number of 1 denote?

A

The aircraft is travelling at the speed of sound

19
Q

How is the Mach number calculated?

A

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

20
Q

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

A

The shock wave

21
Q

What are the three sound regions?

A
  • subsonic
  • transonic
  • supersonic
22
Q

What is the critical Mach number?

A

The maximum speed before the formation of shock waves

23
Q

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

A
Equator = 16 kilometres
Poles = 8 kilometres
24
Q

What are the three parts of the atmosphere?

A
  • Stratosphere
  • Tropopause
  • Troposphere
25
Q

Who introduced the standard atmosphere?

A

The ICAO

26
Q

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

A

11 kilometres

27
Q

What does ISA stand for?

A

International Standard Atmosphere

28
Q

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

A

6.5 degrees per kilometre

29
Q

What is the standard temperature of the tropopause?

A
  • 56.5 degrees Celsius
30
Q

Where in the atmosphere is there no temperature change?

A

The stratosphere

31
Q

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

A

The troposphere

32
Q

What is the equation for speed?

A

Speed = distance
————
time

33
Q

What is the equation for acceleration?

A

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

34
Q

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

A

There is no change to the weight

35
Q

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

A

The weight of the object increases due to the added force

36
Q

What is the formula for dynamic pressure?

A

Pressure = 1/2 P V^2

37
Q

What is the formula for static pressure?

A

P = Pgh

38
Q

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

A

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