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Wood Physics > Lesson 6-8 > Flashcards

Lesson 6-8 Flashcards

1
Q

a branch of physics that studies how energy changes in a system

A

Thermodynamics

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2
Q

deals with the transfer of energy from one place to another and from one form to another

A

THERMODYNAMICS

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3
Q

a form of energy that corresponds to mechanical work

A

Heat

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4
Q

The key concept is that ____ is a form of energy corresponding to a definite amount of ______ _____.

A

heat, mechanical work

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5
Q

Four elements of fire

A

Heat, Oxygen, Fuel, Chemical Reaction

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6
Q

3 WAYS BY WHICH HEAT CAN BE TRANSFERRED

A

Conduction
Convection
Radiation

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7
Q

Heat transfers from molecule to molecule.

A

Conduction

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8
Q

Heat transfers by the movement of heated particles as in air currents.

A

Convection

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9
Q

Energy is in the form of heat or light rays is sent out from atoms and molecules as they undertake internal change.

A

Radiation

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10
Q

4 ESSENTIAL THERMAL PROPERTIES OF WOOD

A
  1. THERMAL CONDUCTIVITY
  2. HEAT CAPACITY
  3. THERMAL DIFFUSIVITY
  4. COEFFICIENT OF THERMAL EXPANSION
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11
Q

usually represented by k

A

THERMAL CONDUCTIVITY

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12
Q

measure of the rate at which heat flows through a specified material

A

THERMAL CONDUCTIVITY

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13
Q

Expressed as the amount of heat that flows per unit time through a unit area subjected to unit temperature difference

A

THERMAL CONDUCTIVITY

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14
Q

Units used to measure the heat flow or heat transfer are

A

W/(m^2/k) or W/(m^2/C)

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15
Q

amount of energy needed to raise the temperature of a specific material by 1 degree celcius

A

Heat Capacity of wood

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15
Q

factors that affect heat capacity of wood

A

temperature and moisture content

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16
Q

Measure of how fast a wood can absorb heat from its nearby environment

A

THERMAL DIFFUSIVITY OF WOOD

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16
Q

It is also defined as the ratio of thermal conductivity to the product of density and heat capacity

A

THERMAL DIFFUSIVITY OF WOOD

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17
Q

Measures the dimensional changes in wood as affected by changes in temperature.

A

COEFFICIENT OF THERMAL EXPANSION IN WOOD

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18
Q

The ovendry thermal expansion coefficients of a sample wood are ______ in all sections

A

positive

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19
Q

If the ovendry thermal expansion coefficients of a sample wood are positive the wood ________/_____ on heating and contracts on cooling.

A

wood swells or expands

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20
Q

4 ESSENTIAL THERMAL PROPERTIES OF WOOD

A
  1. THERMAL CONDUCTIVITY
  2. HEAT CAPACITY
  3. THERMAL DIFFUSIVITY
  4. COEFFICIENT OF THERMAL EXPANSION
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21
Q

Ability to absorb and prevent reflections of sound

A

Acoustic Property

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22
Q

refers to its capacity to absorb or reflect sound and reduce vibrations

A

Acoustic Property

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23
Q

If the wood has a high damping capacity, it is an ideal material for _____ _____ in which ______ __ _______.

A

structural components , vibrations is unwanted.

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23
Q

Wood is acoustic because:

A
  1. Presence of pores, vessel lines, and microcapillaries
  2. Fabricated holes
  3. Fabricated striations
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24
Q

high porosity wood is effective as a sound-absorbing material because it _____ _ ___ ___ _____.

A

exhibits a small specific impedance

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25
Q

essential in the design and construction of musical

A

Fabricated holes

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26
Q

The _____, ____, and ____ of these holes influence the ______, _____, and _____ ____ performance of the instrument

A

placement, size, and shape / resonance, tone, volume, and overall acoustic

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27
Q

It plays a significant role in determining the final sound.

A
  1. craftsmanship of the instrument
    How the wood is:
  2. treated
    3.shaped
    4.assembled
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28
Q

It has a high absorption at high frequencies; effective in reducing echoes.

A

Softwood

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28
Q

It has a moderate reflection; better for diffusing sound.

A

Softwood

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29
Q

It has a lower absorption overall; absorbs less high-frequency sound.

A

Hardwood

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30
Q

It has a high reflection especially at lower
frequencies.

A

Hardwood

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31
Q

The workability of this wood is more challenging, it is better at low frequencies, heavier and have lower reflection

A

Hardwood

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32
Q

Unit used to measure sound, named after Alexander Graham Bell.

A

Decibel

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33
Q

___-___ decibel is the normal level for human.

A

60-70

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34
Q

___ __ is the maximum for safe volume level for ears.

A

80 dB

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35
Q

Capacity of wood to withstand induced
vibration by sound waves transmitted
from the outside forces

A

RESONANCE OF WOOD

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36
Q

Movement of electricity can be classified in two different ways

A

Direct Current (DC) and Alternating Current (AD)

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37
Q

Deals with the movement or flow of energy in the form of electric charge such as electrons.

A

ELECTRICAL PROPERTIES OF WOOD

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38
Q

flow of electric charge in one direction.

A

Direct Current (DC)

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39
Q

flow of electric charge that frequently reverses direction.

A

Alternating Current (AD).

40
Q

DIRECT CURRENT (DC) ELECTRICAL PROPERTIES OF WOOD

A

Resistivity
Conductivity

41
Q

exhibits how strongly it resists the flow of electric current.

A

Resistivity

42
Q

as the MC of wood increases from ovendry to FSP, resistivity _______.

A

decreases

43
Q

as the MC continues to increase from FSP to complete MC saturation in wood, the _____ __ _____ _____.

A

smaller its electrical resistivity

44
Q

The higher the MC the lower the ______.

A

Resistivity

45
Q

reciprocal of electrical resistivity.

A

Conductivity

46
Q

wood’s ability to conduct electric current

A

Conductivity

47
Q

electrical conductivity of wood _____ as
temperature _____ unlike the conductivity of _____.

A

increases, increases, metal

48
Q

the wood conductivity is ___ ___ __ ____ ____ compared to the direction across the grain, and greater in the ____ ____ than in the tangential section

A

greater along the grain direction, radial section

49
Q

The AC electrical properties of wood deals with the ______ _____.

A

dielectric constant

50
Q

also known as relative permittivity

A

Dielectric Constant

51
Q

defined as the ratio of the permittivity of a substance to the permittivity of free space.

A

Dielectric Constant

52
Q

the measure of energy per unit volume stored in wood in the form of electric polarization when the material is in a given electric field.

A

dielectric constant of wood

53
Q

FACTORS AFFECTING ELECTRICAL PROPERTIES OF WOOD

A

MOISTURE CONTENT
TEMPERATURE
WOOD TYPE
GRAIN ORIENTATION

54
Q

IS A WOOD A GOOD CONDUCTOR OR INSULATOR?

A

Insulator

55
Q

What do we call the fundamental properties of wood that describes its ability to permit the transmission of an electric field?

A

Permittivity or Dielectric Constant

56
Q

Branch of science concerned with the behavior of physical bodies when subjected to forces or displacement, and the subsequent effects of the bodies on their environment

A

Mechanics

57
Q

KINDS OF STRESSES IN WOOD

A

➢COMPRESSIVE
STRESS
➢TENSILE STRESS
➢SHEAR STRESS

58
Q

A type of stress that develops when a material is subjected to an external force that tends to squeeze or shorten the wood.

A

COMPRESSIVE STRESS

59
Q

Exerted on a wood if the force tends to increase or to expand the dimension or volume of the wood.

A

TENSILE STRESS

60
Q

Relevant in situations where forces act parallel to the grain, causing adjacent layers of wood fibers to slide or deform.

A

SHEAR STRESS

61
Q

Result from forces that tends to cause portions of a wood to move or slide in parallel but opposite direction.

A

SHEAR STRESS

62
Q

Referred to as the change in length per unit of length in the direction of stress.

A

STRAIN IN WOOD

63
Q

Measure of the deformation or change in the shape of the material that results from the applied force.

A

STRAIN IN WOOD

64
Q

usually expressed in pounds per square inch (psi) or in pascals (Newton per square
meter)

A

Stress

65
Q

the pressure resulting from a force of one pound-force applied to an area of one square inch.

A

psi

66
Q

One (1) psi is equal to _____ pascals, or ____ kg/cm².

A

6,895 , 0.07

67
Q

referred to as the change in length per unit of length in the direction of stress

A

Strain

68
Q

Resistance of the wood specimen from being deformed when stress is applied

A

MODULUS OF ELASTICITY

69
Q

a longer line of MOE means it has a _____ ______ to deformity.

A

greater resistance

70
Q

TYPES OF DEFORMATION IN WOOD

A

ELASTIC DEFORMATION
TOTAL DEFORMATION

71
Q

When there is a sudden change in the shape of wood when load/stress is applied but the change is recoverable when stress is removed

A

ELASTIC DEFORMATION

72
Q

It is the line beyond the stress at proportional limit (red broken lines), where the change in size or shape of the wood when applied with stress is no longer recoverable.

A

TOTAL DEFORMATION

73
Q

Applied force

A

Stress

74
Q

Deformities

A

Strain

75
Q

the wood specimen applied with load/stress parallel to grain has the capacity to withstand the load until it reaches its breaking point

A

MODULUS OF RUPTURE

76
Q

Structural element that carries transverse loads

A

WOODEN BEAMS

77
Q

A piece of wood which is typically long and squared that can be used as a building material.

A

WOODEN BEAMS

78
Q

TYPES OF BEAMS

A
  1. SIMPLE BEAM
  2. CANTILEVER BEAM
  3. CONTINUOUS BEAM
  4. OVERHANGING BEAM
  5. FIXED END BEAM
79
Q

TYPES OF BEAM LOADING

A
  1. DISTRIBUTION OF THE WEIGHT IMPOSED
  2. LENGTH OF TIME WHEN WEIGHT ARE IMPOSED
80
Q

DISTRIBUTION OF THE WEIGHT IMPOSED

A

A. CONCENTRATED LOAD
B. OVERHANGING LOAD
C. DISTRIBUTED LOAD
1.UNIFORMLY DISTRIBUTED LOAD
2.UNIFORMLY VARYING LOAD

81
Q

LENGTH OF TIME WHEN WEIGHT ARE IMPOSED

A

A. STATIC LOAD
B. PERMANENT LOAD (DEAD LOAD)
C. SHOCK LOAD
(IMPACT LOAD)
D. ROLLING LOAD

82
Q

directly support the floor boards.

A

JOIST

83
Q

wooden beam that supports the roofing in an inclined position.

A

RAFTER

84
Q

the ties are placed in bridge
construction longitudinally.

A

STRINGER

85
Q

It is a beam with only one support, either left or right
end, that carries loads or weights on the unsupported
section.

A

CANTILEVER BEAM

86
Q

It is a beam that is supported or rests on two or more supports

A

CONTINUOUS BEAM

87
Q

a beam that is almost similar to a simple beam where in it supported at two points however the loads are carried on the extended portion.

A

OVERHANGING BEAM

88
Q

a beam in which both
ends supports are fixed

A

FIXED END BEAM

89
Q

an extent of pressure due to the overlaid weight or due to the external forces acting on the wooden beam

A

BEAM LOADING

90
Q

It is a load resting at any point in the entire length of the beam.

A

. CONCENTRATED LOAD

91
Q

It is a load resting on the extended portion of the beam.

A

OVERHANGING LOAD

92
Q

The weights are spread over the entire length.

A

DISTRIBUTED LOAD

93
Q

a load which gradually increases in magnitude upon
a stationary beam.

A

STATIC LOAD

94
Q

It is a load where the forces act over a long period of time with no increase in magnitude (floor joist).

A

PERMANENT LOAD (DEAD LOAD)

95
Q
  • load that is suddenly applied
    (ex. Wooden bat that hits the ball).
A

SHOCK LOAD (IMPACT LOAD)

96
Q

load resulting from weights in motion or a load that is moving

A

. ROLLING LOAD

97
Q

refers to the reactions which the wooden beam has obtained because of applied forces.

A

MOMENT

98
Q

branch of mechanics that is concerned with the analysis of loads acting on physical systems (example is wood) that do not experience an acceleration, but rather, are in static equilibrium with their environment.

A

STATICS

99
Q

THREE BASIC LAWS OF STATICS

A
  1. The sum of all vertical forces is equal to zero.
  2. The sum of all horizontal forces is equal to zero.
  3. The sum of all moments is equal to zero.
100
Q

This equation involves rotation. It states that all the moments (or torques) trying to rotate an object in one direction must equal those trying to rotate it in the opposite direction.

A

∑𝑀=0

101
Q

This equation indicates that all the forces acting to the left must equal all the forces acting to the right.

A

∑𝐻=0

102
Q
A

Wood Physics (4 decks)

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