Download Science Grade 8 Daily PACT Review Questions

Science Grade 8 Daily PASS Review Questions
Day
QUESTION
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8-2.1:
What is a species?
8-2.1:
What is an adaptation?
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8-2.2:
them?
What is a fossil and how do scientists use
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8-2.2:
What is the fossil record?
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8-2.2: What is a mold fossil?
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8-2.2:
What is a cast fossil?
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8-2.2:
What is a petrified fossil?
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8-2.2: What is a preserved fossil?
8-2.1: How can biological adaptations enhance the
survival of a population in a particular environment?
ANSWER
A group of organisms that can
breed and produce fertile offspring
A trait that helps an organism
survive and reproduce.
Species (in a particular
environment) that are better
adapted to living conditions in
their environment are able to meet
their survival needs and are more
likely to survive and reproduce
offspring with similar traits.
A fossil is the preserved remains or
traces of an organism that lived in
the past, usually more that 10,000
years ago. Fossils give clues to the
diversity of living things over the
history of Earth, give clues to past
climate and surface changes on
Earth, and give clues to changes
that have occurred within species
of organisms over time.
The millions of fossils collected
and studied, the fossil record, gives
important information about past
life and environments on Earth.
Certain fossilized organisms could
only live in specific environments
or under particular climate
conditions. Extinction of lifeforms, as well as how and when
new life-forms appeared, are part
of the fossil record.
A fossil formed when sediments
bury an organism and the
sediments change into rock; the
organism decays leaving a cavity
in the shape of the organism
Formed when a mold is filled with
sand or mud that hardens into the
shape of the organism.
Formed when minerals soak into
buried remains, replace the
remains, and change them into
rock
Formed when entire organisms or
parts of organisms are trapped in
ice, tar, or amber and are prevented
from decaying
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8-2.2:
What is a carbonized fossil?
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8-2.2:
What is a trace fossil?
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8-2.3: What affected the types of life that first
appeared on earth?
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8-2.3:
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8-2.3: What thrived during the Mesozoic Era and
what caused it to end?
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8-2.4: What is the difference between an era, a period,
and an epoch?
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8-2.4: What era, period, and epoch is modern day
earth in?
Present day Earth is in the
Cenozoic era, the Quaternary
period, and the Holocene epoch.
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8-2.4:
4.6 billion years old
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What characterized the Paleozoic era?
How old is the earth?
8-2.5: What is the geologic time scale; what ends a
geologic era?
8-2.5:
How do scientists use the geologic time scale?
Formed when organisms or parts
of organisms are pressed between
layers of soft mud or clay that
hardens, squeezing almost all the
decaying organism away, leaving
the carbon imprint in the rocks.
Formed when the mud or sand
hardens to stone where a footprint,
trail, or burrow of an organism was
left behind
Earliest life forms were influenced
by the forming atmosphere and
oceans of earth, as well as volcanic
activity and mountain building.
Life (on land) developed and
flourished in the tropical climates.
Many life-forms became extinct at
the end of the Paleozoic Era, yet
fish and reptiles still survived
As reptiles, early birds and
mammals thrived during the
Mesozoic Era, it too came to an
end with mass extinctions,
including the dinosaur species;
possibly due to a world-wide
impact catastrophe and climate
change
eras are divided into periods;
periods can be further divided into
epochs.
The geologic time scale is a record
of the major events and diversity of
life forms present in Earth’s
history. It began when Earth was
formed and goes on until the
present. At the end of each era a
mass extinction occurred and many
kinds of organisms died out.
Using the fossil record,
paleontologists have created a
picture of the different types of
common organisms in each
geologic period.
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8-2.5: Describe what kind of plants and animals
existed during the Paleozoic era. How did the era end?
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8-2.5: Describe what kind of plant and animals
existed during the Mesozoic era. How did the era end?
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8-2.5: Describe what kind of plant and animals
existed during the Cenozoic era. How did the era end?
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8-2.6: What is the law of superposition and what
does it have to do with relative dating?
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8-2.6: What is an index fossil and what makes a
fossil a good index fossil?
Began with the early invertebrates,
such as trilobites and brachiopods;
continued to develop early
vertebrate fish, then arachnids and
insects; later came the first
amphibians, and near the era’s end
the reptiles became dominant,
early land plants included simple
mosses, ferns, then cone-bearing
plants. By the end of the era, seed
plants were common. The mass
extinction that ended the era
caused most marine invertebrates
as well as amphibians to disappear.
Reptiles were the dominant
animals of this era, including the
various dinosaurs. Small
mammals and birds also appeared.
Toward the end of the era,
flowering plants appeared and the
kinds of mammals increased. The
mass extinction that ended the era
caused the dinosaurs to become
extinct.
New mammals appeared while
others became extinct. The
diversity of life forms increased.
Flowering plants became most
common. Humans are also part of
the most recent period of this era.
The law of superposition states that
each rock layer is older than the
one above it. So using this
layering, the relative age of the
rock or fossil in the rock is older if
it is farther down in the rock
layers. Relative dating can be used
only when the rock layers have
been preserved in their original
sequence.
Fossils used to help find the
relative age of rock layers. To be
an index fossil –
• an organism must have
lived only during a short
part of Earth’s history;
• many fossils of the
organism must be found
in rock layers;
• the fossil must be found
over a wide area of Earth;
• the organism must be
unique.
The shorter time period a species
lived, the better an index it is. A
key example of an index fossil is
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8-2.7: Explain natural factors that can lead to
extinctions? Are they good or bad?
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8-2.7: Explain man made factors that can lead to
extinctions? Are they good or bad?
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8-3.1: Describe the crust, the mantle and the core of
the earth.
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8-3.2: What are primary (p) waves?
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8-3.2:
What are the secondary (S) waves?
the trilobite, a hard-shelled animal
whose body had three sections,
lived in shallow seas, and became
extinct about 245 million years
ago.
Organisms that could not survive
changes due to volcanic eruptions
and global warming, global
cooling during ice ages, changes in
oxygen levels in seawater, or a
massive impact from an asteroid or
comet became extinct. Natural
extinctions have occurred
throughout geologic history. Not
all are considered negative in that
extinctions often clear the way for
new kinds of life.
Man-made factors such as the
cutting of the rainforest regions,
removing natural habitats, overharvesting, and pollution have
caused extinctions. Many plants
and animals are likely to become
extinct in the near future if humans
do not make changes in the way
they are damaging earth, and
removing the survival needs of
many organisms. Humans’ damage
to the environment is possibly
threatening some biological
resources that humans may need.
Crust: Outermost layer; thinnest
under the ocean, thickest under
continents; crust & top of mantle
called the lithosphere
The mantle: middle layer, thickest
layer; top portion called the
asthenosphere
The Core: inner layer; two parts
the outer core and inner core
The outer core is mainly slow
flowing liquid. The inner core is
solid.
P waves move out from the
earthquake focus, the point where
the energy is released; they travel
the fastest of the three waves; they
move through solid and liquid
layers of Earth; they push and pull
rock creating a back-and-forth
motion in the direction the wave is
moving.
S waves move out from the
earthquake focus; they move
slower than primary waves; they
can only move through solid rock;
they move at right angles to
primary waves causing rocks to
move up and down and side to side
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8-3.2: What are surface waves?
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8-3.3: How can you infer an earthquake’s epicenter
from seismographic data?
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8-3.4: What is the rock cycle?
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8-3.4: Describe igneous, metamorphic, and
sedentary rocks.
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8-3.6: Explain the motion of lithospheric plates.
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8-3.6:
Describe the three types of boundaries.
Form when P and S waves reach
the surface; they can cause the
ground to shake, making rock sway
from side to side and roll like an
ocean wave.
Use the records from three
seismograph stations to plot circles
on a map. This triangulation will
identify the epicenter where the
three circles intersect.
A series of processes on the
surface and inside the earth that
slowly change rocks from one type
to another
Igneous is formed by the cooling
of metamorphic rock. Sedimentary
is formed when particles of other
rocks or the remains of plants and
animals are cemented together.
Metamorphic rock is formed when
an existing rock is changed by
heat, pressure, or chemical
reactions.
Plates float on the lower part of the
mantle.
Convection currents deep inside
Earth can cause the asthenosphere
to flow slowly carrying with it the
plates of the lithosphere.
This movement of plates changes
the sizes, shapes, and positions of
Earth’s continents and oceans.
Divergent boundary-where two
plates are moving apart;
most located along mid-ocean
ridge (sea-floor spreading);
new crust forms because magma
pushes up and hardens between
separating plates.
Convergent- where two plates
come together and collide;
activity depends upon the types of
crust that meet;
more dense oceanic plate slides
under less dense continental plate
or another oceanic plate –
subduction zone, some crust is
destroyed;
two continental plates converge,
both plates buckle and push up into
mountain ranges;
Transform boundary-where two
plates slide past each other;
crust is neither created nor
destroyed;
Earthquakes occur frequently
along this type of boundary.
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8-4.1: Summarize the characteristics and movements
of objects in our solar system (including planets,
moons, asteroids, comets, and meteors).
Planets: Planets may have a
terrestrial or rocky surface or a
gaseous surface. Gaseous planets
are considerably larger than
terrestrial planets. Planets may
have rings. Some planets have a
unique surface characteristic, for
example color or an atmospheric
storm. Movement of planets are
based on revolution around the
Sun and rotation on the planet’s
axis.
Moons: Moons are studied in
relation to the planet they orbit.
Most are rocky bodies covered
with craters, but some have
unique characteristics. Not all
planets have moons. Movement
of moons is be based on
revolution around their planets.
Specific study of the rotation of
Earth’s moon is essential.
Asteroids: Asteroids are rocky
bodies that orbit in a region of the
solar system known as the
asteroid belt. They vary in size
and shape. Movement should be
based on their revolution around
the Sun.
Comets: Comets have composition
in the main body or head, a tail
that emerges, as the comet gets
closer to the Sun during its orbit;
unique long, narrow elliptical
revolutions.
Meteoroids: Meteoroids are
chunks of rock and move about
within the solar system. The
location and movement
distinguish among a meteor, a
meteoroid, or a meteorite.
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8-4.2: Summarize the characteristics of the surface
features of the Sun: photosphere, corona, sunspots,
prominences, and solar flares.
The Sun’s atmosphere includes the
photosphere and the corona:
• The photosphere makes light
and is the most prominent
layer
of
the
Sun’s
atmosphere.
• During a total eclipse when
the photosphere is blocked,
the corona, the outer layer of
the Sun’s atmosphere that
looks like a white halo, can
be seen.
Other features on or above the
Sun’s surface are sunspots,
prominences, and solar flares.
• Sunspots are areas of gas on
the sun that are cooler than
the surrounding gases and
therefore do not give off as
much light.
• Prominences
are
huge,
looping eruptions of gas,
usually near sunspots, that
arch out into the outer layers
of the Sun’s atmosphere.
• Solar flares are explosions
of hot gas that occur when
prominences connect. They
shoot from the Sun’s surface
releasing
tremendous
amounts of energy into space.
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8-4.5: Explain how the tilt of Earth’s axis affects the
length of the day and the amount of heating on Earth’s
surface, thus causing the seasons of the year.
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The number of daylight
hours changes throughout the
year because Earth’s axis is
tilted 23½ degrees.
• Earth has seasons because
its axis is tilted in the same
direction as it moves around
the sun, not because of any
distance difference between
the Sun and Earth.
• The angle of the Sun’s rays
due to the tilt of Earth’s axis
and the number of daylight
hours causes the differences
in the seasons.
• The combination of direct
rays and more daylight hours
causes Earth to heat up;
slanted rays and less hours of
daylight causes Earth to cool
down.
Students should be able to explain
how the combination of these
factors results in summer and
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8-4.7: Explain the effects of gravity on tides and
planetary orbits.
winter and also the equinox
positions of spring and autumn.
The Moon, being closer to Earth
than the Sun, has the greatest
pulling effect on tides, the rise and
fall of ocean water in this case.
The Sun also pulls on Earth and
can combine its force with the
Moon causing even higher tides,
spring tides, or it can be at right
angles, pulling against the Moon’s
pull, causing very little tidal
change, neap tides.
Planetary
The Sun’s gravitational attraction,
along with the planet’s inertia,
keeps the planets moving in
elliptical orbits (Earth’s orbit is
slightly oval) and determines how
fast they orbit.
Planets nearer the Sun move/orbit
faster than planets farther from the
sun because the gravitational
attraction is greater.
When a planet is farther from the
Sun, the gravitational attraction
between them decreases and the
planet moves/orbits slower.
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8-4.8: What is the difference between mass and
weight?
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8-6.2:
Describe a mechanical wave.
Students should understand this
indicator as a cause (gravity) and
its effects on tides and planetary
orbits.
Mass is the amount of matter in an
object; it does not depend on forces
acting on it.
Mass is the same no matter where
the object is located as long as the
object does not gain or lose any of
its matter.
An object that has mass can be
pulled on by gravitational force.
Weight is a measure of the pull of
gravity on an object.
Weight is related to mass but they
are not the same.
Weight on Earth is based on the
pull of gravity toward the center of
Earth. Weight can change on
Earth. The pull of gravity is not the
same everywhere.
Mechanical waves are waves that
travel through matter. The matter
that waves travel through is called
a mediu,m and it can be a solid,
liquid or gas, or a combination of
these. The particles of matter
vibrate by pushing together and
moving apart, or by moving up and
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8-6.2: Describe an electromagnetic wave.
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8-6.3 Summarize factors that influence the basic
properties of waves (including frequency, amplitude,
wavelength, and speed).
down, as the waves travel through
them to transfer the energy through
the medium. Sound waves, for
example, are mechanical waves
that require particles to vibrate in
order for energy to be transferred.
Sound waves cannot be transferred
or transmitted through space.
Water waves and the waves that
travel down a rope or spring are
also mechanical waves.
Electromagnetic waves are waves
that can travel through empty
space where matter is not present.
Instead of transferring energy from
particle to particle as is done by
mechanical waves, electromagnetic
waves transfer energy through
space. Radio waves, microwaves,
infrared rays, visible light,
ultraviolet rays and x-rays are all
forms of energy that travel in
electromagnetic waves.
Wavelength is the distance between
one point on a wave and the
nearest point just like it. The
wavelength is the measure of the
distance between any two
successive identical parts of wave.
The greater the energy carried by
waves, the smaller the
wavelength.
Frequency is the number of full
wavelengths that pass a point each
second. The frequency of a wave
also measures how rapidly
vibrations occur in the medium, at
the source of the wave, or both.
The greater the energy carried by
waves, the greater the frequency.
Amplitude is the greatest distance
that vibrations in a wave move
from their normal position when a
wave passes by. The greater the
wave’s amplitude, the more
energy the wave carries.
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8-6.4: Summarize the behaviors of waves using
refraction, reflection, transmission and absorption.
Refraction is the bending of waves
caused by a change in their speed
as they pass from one medium to
another. As waves pass at an angle
from one medium to another, they
may speed up or slow down. The
greater the changes in speed, the
more the waves bend.
Reflection is the bouncing back of
a wave when it meets a surface or
boundary that does not absorb the
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8-6.5: Explain hearing in terms of the relationship
between sound waves and the outer, middle, an inner
ear.
entire wave’s energy. All types of
waves can be reflected.
Reflections of sound waves, for
example, are called echoes and
help bats and dolphins learn about
their environments.
Transmission of waves occurs
when they pass through a given
point or medium.
Absorption of waves occurs when
the energy is not transferred
through the given medium or
space. Absorption of waves
causes the following behaviors
depending on what type of wave
is absorbed:
Color The color of the object
depends on the light wavelengths
that are absorbed and reflected.
Substances that absorb certain
wavelengths of light reflect other
wavelengths and have specific
colors that are characteristics of
that substance.
Temperature Change
Objects or substances that absorb
infrared radiation become
warmer as the infrared radiation
is transformed to thermal (heat)
energy by causing particles in the
substance to move at a faster rate.
Outer ear: Sound waves are
gathered by the outer ear made up
of the ear, the ear canal, and the
eardrum. The outer ear is shaped
to help capture the sound waves
(energy transferred in particles of
air) and send them to the ear canal
which transfers them to the
eardrum. The vibrations of air
particles cause the eardrum to
vibrate.
Middle ear: The middle ear
amplifies sound waves.
Inner ear: The inner ear transmits
vibrations from the bones of the
middle ear to the liquid in the
inner ear. The tiny hairs in the
inner ear vibrate as the liquid
vibrates. The vibrating tiny hairs
transmit the energy to nerves
attached to the hairs. The nerve
impulses are transmitted to the
brain for connections in the brain
for understanding of the sound as
“hearing.”
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8-6.6
Explain sight in terms of the relationship
between the eye and the light waves emitted
or reflected by an object.
It is essential for students to know
the interaction between the major
parts of the eye and light emitted
or reflected by an object to allow
sight to occur as follows:
The cornea is a transparent tissue
that transmits and refracts light to
the pupil, the opening in the iris of
the eye in front of the lens.
The lens refracts the light further
and focuses the light waves on the
retina.
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8-6.8: Compare visible light and ultraviolet light as
far as wavelengths and the energy of the waves they
possess.
8-5.1: How can you use a graph to show position,
direction, and speed?
The retina is located on the back
of the inside of the eye and is
composed of tiny nerves that
transfer the energy of the light
waves to nerve impulses
transmitted to the brain for
interpretation as sight.
Visible light is the range of
electromagnetic waves that can be
detected by the human eye. The
wavelengths are in the middle
range of wavelengths of
electromagnetic waves. Visible
light is also in the middle of the
energy range of electromagnetic
waves. The longer the
wavelength, the lower the energy
of the wave. The eye reacts to
different energies and
wavelengths of light so that
different colors are seen. Shorter
wavelengths are perceived as
violet colors and longer
wavelengths are perceived as red
colors. Shorter, violet
wavelengths are higher energy
levels than longer, red
wavelengths of visible light.
Ultraviolet radiation
Ultraviolet radiation has
smaller wavelengths than violet
wavelengths of visible light.
Ultraviolet radiation is higher in
energy than visible light.
Position: You can tell position
relative to a reference point on the
X-axis
The direction of the object is
described as whether it is “moving
away” from or “moving toward”
the reference point. If the object is
“moving away” from the
reference point, the line will go up
Department of Curriculum and Instruction 1/29/2009
(distance increasing). If the object
is “moving toward” the reference
point the line will go down
(distance decreasing).
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8-5.2 Use the formula for average speed, v=d/t, to
solve real world problems: An airplane is flying at a
constant speed of 150 meters per second. After one
hour, how far has the plane traveled?
8-5.3: How does gravity affect the speed and
direction of an object?
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8-5.3: How does friction affect the speed and
direction of an object?
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8-5.4: Predict how varying amounts of force or mass
will affect the motion of an object.
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8-5.5: Analyze the effect of a balanced force on an
object’s motion and in terms of magnitude and
direction
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8-5.5: Analyze the effect of an unbalanced force on
an object’s motion and in terms of magnitude and
direction
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Speed The slope of the line can
tell the relative speed of the object.
When the slope of the line is steep,
the speed is faster than if the slope
were flatter. When the slope of the
line is flatter, the speed is slower.
d=vt = (150 m/sec) x (3,600 sec)
= 540,000 meters or
= 540 kilometers
Gravity, which is a property of all
matter, is a force that pulls objects
toward each other without direct
contact or impact. Objects on
Earth are pulled toward the center
of Earth and when raised above
the surface of Earth, they fall
“down” toward Earth. As objects
fall toward Earth, their speed
increases at a definite rate.
Friction is a force that opposes
motion. It can slow down or stop
the motion of an object. The
slowing force of friction always
acts in the direction opposite to
the force causing the motion. For
example, friction slows or stops
the motion of moving parts of
machines. Most tires are designed
to increase friction for better
traction on the road.
Force The greater the force
exerted on an object, the
faster an object will
move.
Mass The greater the mass of
an object with the same
force exerted on it, the
slower the object will
move.
Balanced forces do not cause a
change in the magnitude or
direction of a moving object.
Objects that are not moving will
not start moving if acted on by
balanced forces
Unbalanced forces are not equal,
and they always cause a change in
the magnitude and direction of a
moving object. When two
unbalanced forces are exerted in
opposite directions, their combined
force is equal to the difference
between the two forces and is
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8-5.6: Summarize and give an example of the
concept of inertia.
exerted in the direction of the
larger force. If unbalanced forces
are exerted in the same direction,
the resulting force will be the sum
of the forces in the direction the
forces are applied.
It is essential for students to know
that inertia is the tendency of
objects to resist any change in
motion. It is the tendency for
objects to stay in motion if they are
moving or to stay at rest if they are
not moving unless acted on by an
outside force. Examples of the
effects of inertia are:
• Inertia causes a passenger
in a car to continue to
move forward even
though the car stops.
• Inertia is why seat belts
are so important for the
safety of passengers in
vehicles.
Inertia is why it is impossible for
vehicles to stop instantaneously
Department of Curriculum and Instruction 1/29/2009