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98 Cards in this Set
- Front
- Back
What are the three broad categories of
measurement? |
a. Magnitude
b. Direction c. Time |
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What unit of measurement is used to
express scientific measurements? |
Metric unit of measurement
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Match the element being measured with the
metric term used to express the measurement. 1. Distance a. Kilogram 2. Time b. Second 3. Mass c. Meter |
ELEMENT METRIC TERM
1. Distance c . Meters 2. Time a . Seconds 3. Mass c. Kilograms |
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What is the English equivalent of 1 meter?
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Approximately 1 yard
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What is the difference between the mass of
a body and the weight of a body? |
The mass of- the body is the measure of the quantity of matter
that the body contains, and it does not change. The weight of a body is the force that attracts toward earth. |
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What is meant when a person is described as weighing 195 pounds?
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The person has the same pull of gravity that a mass of 195 would
have when located near sea level. |
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How are derived units constructed?
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They are based on combinations of two or three fundamental
units expressed as some combination of these units. For example, the watt could be written as a joule per second. |
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Speed and velocity are sometimes used us
if they meant the same thing. What is the difference between speed and velocity? |
Velocity is a vector quantity; it is speed in a given direction, while
speed is a body moving along a path with no reference being made to direction. |
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What term is defined as the work done in
lifting 1 pound a distance of 1 foot against the force of gravity? |
Foot-pound
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List the measurements included in the units
of power. |
a. Force
b. Distance c. Time |
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What relationship is defined by the
equation E=mc2? |
The law of conservation for energy and matter which states that
“Although the total amount of matter and energy remains constant, matter can be converted into energy or energy into matter.” |
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Name the concept of the statement “Two
objects can’t occupy the same space at the same time.” |
Impenetrability of matter.
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What action must be applied to an object
to overcome inertia? |
A push or pull that exerts a force on the body.
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What is meant by the term acceleration?
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An increase or decrease in speed and/or a change in direction
of motion. |
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Why is force considered a vector quantity?
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Because it has both direction and magnitude.
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In the English system of measurement, what
force is expressed in pounds? |
The gravitational force exerted by the earth on the body, known
as weight of that body, expressed in force units. |
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How is the density of a substance
described? |
It is its weight per unit volume.
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How is the specific gravity of a substance
described? |
It is the ratio of the density of the substance to the density of
water. |
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Moving bodies have energy because they
can do work. What term describes the energy of mass in motion? |
Kinetic energy.
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What gives a substance its distinguishing
characteristics? |
The combination and arrangement of the subatomic particles.
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List the three subatomic particles of the
atom. |
Electron, proton, and neutron.
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What is a balanced atom?
|
An atom that contains an equal number of protons and
neutrons. |
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How is the atomic number of an element
determined? |
By the number of protons in its nucleus.
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How is the atomic weight of an element
determined? |
By the number of protons and neutrons in its nucleus.
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The outer electron shell of each atom of an
element is completely filled. What type of element is this? |
Inert.
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Name the smallest unit that exhibits the
distinguishing characteristics of a compound. |
Molecule.
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In forming a compound, what part of the
atom changes? |
The electron outer shell only. There is no change in the nucleus
of either atom, and the total number of electron ’s hasn’t changed, they’ve been rearranged. |
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List the states of matter.
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a. Solid
b. Liquid c. Gas |
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List the common properties of solids.
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a. Cohesion and adhesion
b. Tensile strength c. Ductility d. Malleability e. Hardness f. Brittleness g. Elasticity |
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List the advantages of liquids as applied to
aviation. |
a. Component parts of a system can be placed at separated
points b. Hydraulic energy is transmitted around corners without gears and levers |
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What is one of the main uses of absolute
zero? |
To study the kinetic theory of gases.
|
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List the absolute zero points on the Kelvin
and Celsius scales. |
a. 0 Kelvin
b. -273° Celsius |
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Name the person who formulated the
following conclusion: “For a constant temperature, the product of the volume and pressure of an enclosed gas remains constant.” |
Boyle.
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Charles’ law states that ________________.
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“All gases expand and contract in direct proportion to the change
in the absolute temperature, pro vialed the pressure is held constant.” |
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Name the branch of physics that deals with
force, mass, and motion. |
Mechanics.
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Describe the point of an object that is its
center of gravity. |
The point where a single force, equal to the gravitational force
and directed up, sustains the body at rest. |
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List the two classes of circular motion.
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Rotation and revolution.
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Generally, a gyro rotor (a) revolves or (b)
rotates about its axis. |
Rotates about its axis.
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What type of force is an accelerating force
applied to the center of gravity of a body so that the body is accelerated with no rotation? |
A translational force.
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How much power is being expended if a
man lifts 50 pounds 5 feet to put it on a shelf in 15 seconds? |
a. First, solve for amount of work being done:
work = force x distance, or work = 50 x 5 = 225 foot-pounds of work b. Next, solve for power expanded to do the work: power = work/time, or power = 225/15 = 15 foot-pounds per second |
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When does an object have potential energy?
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When it can do work, such as a wound clock spring or a cylinder
of compressed gas. |
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What is lost whenever energy is expended?
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Efficiency.
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What is the most common reason for
efficiency loss in mechanical physics? |
Friction.
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What type of bearing is used in many types
of machinery to minimize friction and maximize efficiency? |
Self-lubricating bearings.
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Name the principle that allows man to accomplish
work that he normally could not do. |
Mechanical advantage.
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What force prevents a revolving object
from continuing along a straight line? |
Centripetal force.
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When an object is revolving, what force
tries to oppose centripetal force? |
Centrifugal force.
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What are the characteristics that all types
of waves have in common? |
a. Transmission
b. Reflection c. Refraction d. Absorption |
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Energy is transferred in a medium by a
disturbance that may have an elastic deformation, a pressure variation, an electric or magnetic intensity, an electric potential, o r temperature. Continuous variations induced in to a medium is known as a? |
Wave train. This is a series of waves produced by continuous
variations. |
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Electromagnetic waves are what types of
waves? |
They are transverse waves because the disturbance takes place
at right angles to the direction of propagation. |
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Air is elastic; therefore, a disturbance is
transmitted progressively out ward as a compression wave. What type of waves behave in this manner? |
Longitudinal waves. They behave this way because the
disturbance takes place in the direction of propagation. The waves move back and forth in the direction of wave travel. |
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How are standing waves produced?
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They are produced by two wave trains of the same type and equal
frequency traveling in opposite directions in the same medium. As two waves traveling in opposite directions meet, they combine with each other, and they cease to exist in their original form. |
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A ray is traveling through a medium in a
straight line. What would cause the ray to change its direction? |
It would change its direction if it reached the boundary of a media
or if it reached an area within the media where the velocity of propagation of the wave changes. |
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What happens when a wave is directed
against a reflecting surface? |
The wave is thrown back from the surface. The ray that strikes
the surface is the incident ray and the ray the bounces back is the reflected ray. |
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“The angle of incidence is equal to the angle
of reflection.” What is meant by this statement? |
The path of a ray reflected from a surface forms an angle that
is exactly equal to the one formed by the path of the ray reaching the medium (law of reflection). |
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As a wave passes from one medium into
another, what causes refraction? |
As a wave travels through one medium it is traveling at a specific
velocity of propagation. When it reaches a new medium, the velocity of propagation changes. If the ray is not perpendicular to the boundary between the two media, the ray will change direction and bend. This is known as refraction. |
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What are the two factors that determine the
angle of refraction? |
a. The angle of incidence
b. The index of refraction |
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What causes diffraction?
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Diffraction occurs when the path of waves is bent because of
an obstruction. |
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What is the cause of the Doppler effect?
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The relative motion between the source of a wave and a detector
of that wave. The frequency of the wave at the detector position differs from the frequency of the wave at the source. |
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In the radiation theory, heat is generally
treated the same way as several forms of energy. List these forms. |
a. Radio waves
b. Heat c. Light |
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List the three methods of heat transfer.
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a. Conduction
b. Convection c. Radiation |
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Wood handles are used on soldering irons
because they are ______________________. |
Poor conductors of heat
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In what state is matter the poorest
conductor of heat? |
Gas
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Convection is the process of heat transfer
by means of a hot fluid. Name the aid used in airborne installations to aid convection. |
Fans and blowers
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For an object to become a good absorber
of heat, it is normally painted _________. |
Dull black
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Convert 96°F to the Celsius scale.
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5/9(96 - 32) = 5/9 * 64 = 35.5 DEGREES CELCIUS
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List the four types of scales.
|
a. Celsius
b. Fahrenheit c. Kelvin d. Rankine |
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What principle is involved in temperaturesensitive
switches? |
Coefficient of linear expansion.
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What type of thermometer is usually used
in the laboratory? In aircraft? |
The liquid thermometer is usually used in the laboratory white
the solid thermometer is used in aircraft. |
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What other principle is used to construct
a thermometer? |
The principle of the compound bar.
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What effect does the heat of fusion have
on solder? |
It causes it to become mushy before it melts; that is, it flows
at a very slow rate. |
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List the effects on light waves when they
meet a substance. |
a. Transmitted through the substance.
b. Reflected by the substance c. Absorbed by the substance |
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What is meant by the term luminous
intensity? |
It is the total light produced by a source.
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What is meant by the term intensity of
illumination? |
It is the amount of light received per unit area at a distance from the source.
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What is measured by the footcandle?
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Intensity of incident light.
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What term is usually used to describe the
output of a light bulb? |
lumen.
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What are the principle uses of reflectors?
|
a. To focus a beam of light
b. To change the direction of a light beam. c. To intensify the illumination of an area. |
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What happens when light passes through
a transparent substance? |
It is refracted.
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List the objects that act as refractors.
|
a. Prisms
b. Positive lenses c. Negative lenses |
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Name the primary colors of light frequencies.
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a. Red
b. Green c. Blue |
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If you mix the primary colors together,
what is the result? |
White light.
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List the three components that are required
by sound. |
a. A source
b. A medium for transmission c. A detector |
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List the two properties of a medium that
govern the velocity of sound as it passes through the medium. |
a. Density
b. Elasticity |
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Sound travels faster in liquids and solids
than in gases even though liquids and gases are more dense. Why will sound travel faster in water than it does in air? |
Because of the elasticity of water, sound travels over four times faster in water than in air. The coefficient of elasticity for water is 15,230 times that of air.
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The velocity of sound is lower at high
altitudes. Explain why this is so. |
Velocity is constant in a medium when temperature is constant. If temperature rises, density diminishes, and the velocity of sound increases. Therefore, if temperature drops, density increases, and the velocity of sound decreases. Because air temperature is normally lower at high altitudes, the velocity of sound is lower.
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List the three characteristics of sound.
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a. Pitch
b. Intensity c. Quality |
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What two terms describe the range of sound
the human ear can distinguish? |
The threshold of audibility and the threshold of feeling.
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How do sound units vary with amplitude of
variations? |
Units of sound vary logarithmically with the amplitude of the sound variations.
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The units of sound measurement are the bel
and the decibel. They vary logarithmically with the amplitude of the sound variations. To what do the bel and the decibel refer? |
The bel and the decibel refer to the difference between sounds of unequal intensity or sound levels. The decibel describes the ratio of two sound levels.
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In sound-system engineering, what ratio does
dB express? |
The ratio between electrical powers or between acoustical powers.
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What is the arbitrary zero reference level
used to describe the loudness of sounds? |
The zero reference level is the sound produced by 10 to the negative 16th watts per square centimeter of surface area that faces the source. It is the least sound perceptible to the ear and is also known as the threshold of audibility.
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Name some of the uses of the decibel as it
is used to express an electrical power ratio. |
a. Gain of an amplifier
b. The output of a microphone c. The power in a circuit compared to an arbitrarily chosen reference level |
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What type of acoustical disturbance causes
an echo? |
A reflection of sound waves
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A loudspeaker is being used in a fairly large
room and is producing considerable echo that limits the usefulness of the speaker. List four ways that the effects of echo can be corrected or modified. |
a. Cover the surface with a material that absorbs sound and reduces the intensity of the reflected sound.
b. Change the contour of the surface and aim the reclected sound in another direction c. Change the position of the loudspeaker d. Vary the amplitude or pitch of the signal |
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What is the effect of excessive reverberation
in a large area when a loudspeaker is being used? |
Sound becomes confusing and speech in unintelligible.
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Describe action that can be taken to lessen
or eliminate reverberation in a large area, such as a hangar deck. |
Mount several speakers in the area. This action allows speech to be heard in a reverberant space. Also, the power requirements should remain the same; for example, use five speakers consuming 5 watts instead of one speaker consuming 25 watts.
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Describe the effect of beat frequency.
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Two waves traveling in the same direction and having different frequencies porduce additive disturbances at some points and subtractive disturbances at other points on relative positions of the waves. The resultant wave has a periodic variation in intensity at a frequency equal to the difference between the original frequencies of the components waves. This difference frequency (beat frequency) produces a pulsating interference of alternately loud and soft pulses or throbs.
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Why is resonance potentially a serious
problem? |
Because it can damage equipment.
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