# Physics Flashcards Preview

## BTEC Unit 5 > Physics > Flashcards

Flashcards in Physics Deck (106)
1
Q

How do you convert from cm to m?

A

divide by 100

2
Q

what are the units for energy?

A

Joules

3
Q

How do you convert oC into K

A

+273

4
Q

What is work done

A

the energy transferred from one store to another

5
Q

In the equation for work done

Delta W = F x Delta s

What does F stand for?

A

Force

6
Q

In the equation for work done

Delta W = F x Delta s

What does Delta s stand for?

A

change in displacement

7
Q

In the equation for work done

Delta W = p x Delta V

What does p stand for?

A

pressure

8
Q

In the equation for work done

Delta W = p x Delta V

What does Delta V stand for?

A

Change in volume

9
Q

what is the equation for kinetic energy?

A

0.5 x mass x velocity squared

10
Q

what is the equation for elastic energy?

A

0.5 x spring constant x extension squared

11
Q

what is the equation for gravitational potential energy?

A

GPE= gravity x height x mass

12
Q

what is the definition for power?

A

power is the amount of energy transferred per second

13
Q

what is the equation for power?

A

power = work done divided by time

or

power = energy transferred divided by time

14
Q

what is the equation for pressure?

A

pressure= force divided area

15
Q

described what the origin of gas pressure is

A

particles that have a lot of kinetic energy causes the particles to collide which exerts a force on each other and on the container

16
Q

In the ideal gas equation:

pV = NkT

What does T stand for?

A

temperature

17
Q

In the ideal gas equation:

pV = NkT

What does N stand for?

A

number of particles

18
Q

In the ideal gas equation:

pV = NkT

What does V stand for?

A

volume

19
Q

In the ideal gas equation:

pV = NkT

What does p stand for?

A

pressure

20
Q

what is the equation for Boyles law?

A

pressure x volume = constant

21
Q

what is thermal equilibrium?

A

when all states within a system are at the same temperature

22
Q

define temperature

A

the measure of average kinetic energy of particles

23
Q

The formula for energy transferred when a substance changes temperature is given by:

Delta Q = m x c x Delta T

What does Delta T mean?

A

change in temperature

24
Q

The formula for energy transferred when a substance changes temperature is given by:

Delta Q = m x c x Delta T

What does c mean?

A

specific heat capacity

25
Q

The formula for energy transferred when a substance changes temperature is given by:

Delta Q = m x c x Delta T

What does Delta Q mean?

A

change in heat or energy transferred

26
Q

The formula for energy transferred when a substance changes temperature is given by:

Delta Q = m x c x Delta T

What does m mean?

A

mass

27
Q

In the equation for energy transferred when a substance changes state:

Delta Q = m x L

What does L stand for?

A

Specific latent heat

28
Q

What is the definition for specific heat capacity?

A

the energy required to change the temperature of 1 kg of substance by 1K

29
Q

what is the definition of specific latent heat ?

A

the energy required to change state of 1kg of substance

30
Q

What is Latent fusion?

A

Change of state between solid and liquid e.g melting and freezing

31
Q

What is latent vaporisation?

A

Change of state between liquid and gas e.g boiling and condensing

32
Q

What is internal energy?

A

the sum of kinetic and potential energy of particles

33
Q

In the equation for the first law of thermodynamics:

Delta U = Q - W

What does W mean?

A

work done by the system

34
Q

In the equation for the first law of thermodynamics:

Delta U = Q - W

What does Q mean?

A

35
Q

In the equation for the first law of thermodynamics:

Delta U = Q - W

What does Delta U mean?

A

Change in internal energy

36
Q

What is an adiabatic reaction? (3 factors)

A

no net transfer of heat -

Q = 0

Fast process

37
Q

What is an isothermal reaction? (3 factors)

A

constant internal temperature

slow temperature change

Q = W

38
Q

What does the 2nd law of thermodynamic state?

A

entropy (measure of disorder) always increases

39
Q

The diagram shows a carnot cycle

Label 4 –> 3

A

40
Q

The diagram shows a carnot cycle

Label 1 –> 4

A

isothermal compression

41
Q

The diagram shows a carnot cycle

Label 2 –> 1

A

42
Q

The diagram shows a carnot cycle

Label 3 –> 2

A

Isothermal expansion

43
Q

What does boyles law state?

A

that N and T are constant and that P and V are constant

44
Q

What is the definition of elasticity?

A

the ability for an object to stretch and return back to its original state once the force is removed

45
Q

What does Hooke’s Law state?

A

states that force and extension are directly perportional

46
Q

In the equation for Hooke’s law?

F = k x Delta x

What does k mean?

A

Spring constant

47
Q

In the equation for Hooke’s law?

F = k x Delta x

What does F mean?

A

Force

48
Q

In the equation for Hooke’s law?

F = k x Delta x

What does Delta x mean?

A

Extension or change in length

49
Q

How can you tell from a graph that a material is obeying Hooke’s law?

A

The line is straight

50
Q

For a force-extension graph what does the gradient show?

A

shows the spring constant

51
Q

For a force-extension graph what does the area below the graph show?>

A

Shows how much work is being done

52
Q

On the graph what does point E label?

A

breaking point

53
Q

On the graph what does point B label?

A

elastic limit

54
Q

On the graph what does point A label?

A

limit of proportionality

55
Q

Define stress?

A

The force per unit area of a material

56
Q

What is the equation for stress?

A

stress = force / cross sectional area

57
Q

What is the unit for stress?

A

N/M2

58
Q

Define strain?

A

extension per unit length

59
Q

What is the equation for strain?

A

extension / original length

60
Q

What is the unit for strain?

A

no unit

61
Q

What is the equation for young’s modulus?

A

E= stress / strain

62
Q

Define young’s modulus?

A

measures stiffness of the material (stiffness constant)

63
Q

Look at the stress/stress diagram. Which line represents a elastic material

A

C

64
Q

Look at the stress/stress diagram. Which line represents a brittle material

A

B

65
Q

Look at the stress/stress diagram. Which line represents a ductile material

A

D

66
Q

What does the gradient represent on the young’s modulus

A

it represents how stiff the material is

67
Q

Up to what point of the youngs modulus apply to ?

A

the limit of proportionality.

68
Q

Define brittle?

A

hard but liable to break (little or no plasticity)

69
Q

Define ductile?

A

the ability to be shaped by plastic flow under tension

70
Q

Define creep deformation?

A

slow version of plastic deformation but at a high temperature

71
Q

Define malleable?

A

ability to be shaped by plastic flow under compression

72
Q

Define fatigue?

A

weakness in a metal or other materials caused by repeated variations of stress

73
Q

Define ultimate tensile stress?

A

highest stress a material can sustain just before it breaks

74
Q

Define yield strength?

A

The stress at which plastic deformation starts

75
Q

Define density?

A

amount of substance per unit volume

76
Q

In the equation for density

p = m / V

what does V stand for? What are the units?

A

volume, m3

77
Q

In the equation for density

p = m / V

what does m stand for? What are the units?

A

mass, kg

78
Q

In the equation for density

p = m / V

what does p stand for? What are the units?

A

density, kg/m3

79
Q

Define fluid

A

a substance that has no fixed shape and yields easily to an external force

80
Q

Describe a laminar flow?

A
• parallel path flows -slow and constant -less air resistance
81
Q

Describe a turbulent flow?

A

-irregular flow -fast but inconsistent -more air resistance

82
Q

Describe viscosity?

A

the state of being thick, sticky, and semi-fluid in consistency

83
Q

What is the unit for viscosity?

A

kgm-1s-1

84
Q

What are the 3 factors that affect viscosity?

A

-temperature -molecular structure -pressure

85
Q

How does temperature affect viscosity of a liquid?

A

as temp increases the viscosity of the liquid lowers as it becomes easier for molecules to slide past each other

86
Q

how does temperature affect a gas?

A

the increase in kinetic energy created collisions

87
Q

What are newtonian fluids?

A

-predictable response to force -consistent viscosity

88
Q

What are non-newtonian fluids?

A

-unpredictable response to force -inconsistent viscosity

89
Q

Describe diliant (shear-thickening) how does the viscosity change?

A

changes viscosity when a force is applied viscosity rises with a rise in shear strain

90
Q

Describe pseudoplastic (shear-thinning) how does the viscosity change?

A

when you apply a force it gets thinner viscosity decreases with a rise in shear strain

91
Q

Describe rheopectic how does the viscosity change?

A

-time dependent when applying stress fluid gets thicker when no stress it starts to get thin -more viscous when stressed

92
Q

Describe thixotropic how does the viscosity change?

A

-fluids thin gradually on stirring then slowly reset -less viscous overtime when stressed

93
Q

Describe Bingham plastics how does the viscosity change?

A

-behaves like a solid at low stress but above a yield stress they begin to flow -solid at low stress and as a viscous fluid at higher stress

94
Q

How do you convert from MW to W?

A

x 1000000

95
Q

How do you convert from km to m?

A

/ 1000

96
Q

How do you convert from mW to W?

A

/ 1000

97
Q

How do you convert from GJ to J?

A

x 1000000000

98
Q

What is the unit for power?

A

Watts

99
Q

What is the unit for work done?

A

Joules (J)

100
Q

Name two units for pressure?

A

Pa and N/m2

101
Q

What is the unit for force?

A

Newton (N)

102
Q

What three factors affect gas pressure?

A

temperature, volume of gas and number of particles

103
Q

In which state do particles have the most kinetic energy?

A

gas

104
Q

In which state do particles have the least kinetic energy?

A

solid

105
Q

In which state do particles have the most internal energy?

A

gas

106
Q

In which state do particles have the strongest intermolecular forces?

A

solid