Modified True/False
Indicate
whether the sentence or statement is true or false. If false, change the identified word or
phrase to make the sentence or statement true.
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1.
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Unbalanced forces maintain motion at constant velocity.
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2.
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The
property of matter that resists a change in motion is called inertia.
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3.
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According to Newton’s second law of motion, force equals mass times
weight.
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4.
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Friction depends on the types of surfaces involved and how hard the surfaces
push together.
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5.
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The
force of gravity decreases as the masses of objects increase.
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6.
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When
the only force acting on a falling object is air resistance, the object is said to be in free
fall.
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7.
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Newton’s third law of motion explains that forces act alone.
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8.
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A
unit of momentum is kg•m/s.
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9.
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A
rocket will move upward as long as the thrust is greater than the pull of
gravity.
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10.
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The
force that keeps a satellite in Earth orbit is always directed away from the center of
Earth.
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Multiple Choice
Identify the
letter of the choice that best completes the statement or answers the question.
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11.
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Which
of the following is an example of exerting a force? a. | a child running
through a field | b. | a train speeding down a track | c. | a carpenter
hammering a nail | d. | an airplane soaring through the sky | | |
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12.
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What
happens when two forces act in the same direction? a. | They cancel each
other out. | b. | The stronger one prevails. | c. | They add
together. | d. | Their sum divided by two is the total
force. | | |
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13.
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The
tendency of an object to resist change in its motion is known as a. | mass. | b. | inertia. | c. | force. | d. | balance. | | |
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14.
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The
greater the mass of an object, a. | the more force it can exert. | b. | the greater its
inertia. | c. | the more balanced it is. | d. | the more space
it takes up. | | |
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15.
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Force
= mass • a. | speed. | b. | motion. | c. | acceleration. | d. | inertia. | | |
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16.
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One
way to increase acceleration is by a. | increasing mass. | b. | decreasing
mass. | c. | decreasing force. | d. | increasing both
force and mass equally. | | |
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17.
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The
force that one surface exerts on another when the two rub against each other is
called a. | friction. | b. | acceleration. | c. | inertia. | d. | gravity. | | |
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18.
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Which
of the following is an example of rolling friction? a. | your shoes on a
sidewalk as you walk | b. | bike tires on the road as you ride | c. | a boat on the
water as it sails | d. | two hands rubbing together | | |
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19.
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When
the only force acting on a falling object is gravity, the object is said to be a. | stationary. | b. | decelerating. | c. | in free
fall. | d. | a projectile. | | |
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20.
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Air
resistance is a type of a. | motion. | b. | acceleration. | c. | velocity. | d. | friction. | | |
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21.
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The
force of gravity on a person or object at the surface of a planet is known as a. | mass. | b. | inertia. | c. | air
resistance. | d. | weight. | | |
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22.
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Weight = mass • a. | force due to balanced forces. | b. | acceleration due
to gravity. | c. | inertia due to force. | d. | air
resistance. | | |
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23.
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The
law of universal gravitation states that any two objects in the universe, without
exception, a. | attract each
other. | b. | repel each other. | c. | combine to
provide a balanced force. | d. | create friction. | | |
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24.
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If
you were on the moon, your weight would be roughly what fraction of your weight on
Earth? a. | one
third | b. | one fourth | c. | one
fifth | d. | one sixth | | |
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25.
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Two
figure skaters who push off of each other will move at the same speed if a. | they push with
the same force. | b. | the ice does not cause any friction. | c. | there is no air
resistance. | d. | they have the same mass. | | |
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26.
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Forces can be added together only if they are a. | acting on the
same object. | b. | balanced forces. | c. | unaffected by
gravity. | d. | substantial. | | |
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27.
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The
product of an object’s mass and velocity is called its a. | inertia. | b. | momentum. | c. | acceleration. | d. | force. | | |
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28.
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According to the law of conservation of momentum, when two objects collide in the
absence of friction, a. | velocity decreases. | b. | velocity
increases. | c. | momentum is not lost. | d. | only the object
with the larger mass continues on. | | |
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29.
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The
achievement of lifting a rocket off the ground and into space can be explained by a. | Newton’s
first law. | b. | Newton’s second law. | c. | Newton’s
third law. | d. | the law of conservation of momentum. | | |
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30.
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What
is required for a rocket to lift off into space? a. | thrust that is greater than Earth’s
gravity | b. | mass that is greater than
Earth’s | c. | very little air resistance | d. | more velocity
than friction | | |
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31.
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An
object that travels around another object in space is called a a. | projectile. | b. | inertia. | c. | mass. | d. | satellite. | | |
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32.
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Any
force that causes an object to move in a circle is called a a. | balanced
force. | b. | unbalanced force. | c. | gravitational
force. | d. | centripetal force. | | |
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33.
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In
physical science, a push or a pull is called a(n) a. | force. | b. | acceleration. | c. | inertia. | d. | motion. | | |
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34.
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The
momentum of an object is in the same direction as its a. | force. | b. | acceleration. | c. | velocity. | d. | inertia. | | |
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35.
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How
can you increase the momentum of an object? a. | by decreasing its velocity | b. | by increasing
its mass | c. | by increasing its friction | d. | by decreasing
its acceleration | | |
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36.
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The
amount of matter in an object is called its a. | inertia. | b. | mass. | c. | force. | d. | balance. | | |
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37.
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Which
of the following is an example of increasing friction intentionally? a. | waxing
skis | b. | adding grease to
gears on a bike | c. | throwing sand on an icy driveway | d. | oiling a squeaky
door | | |
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38.
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The
force that pulls falling objects toward Earth is called a. | gravity. | b. | free fall. | c. | acceleration. | d. | air resistance. | | |
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39.
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A
leaf flutters instead of dropping straight to the ground when it falls from a tree because it
experiences a. | terminal
velocity. | b. | air resistance. | c. | inertia. | d. | rolling friction. | | |
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40.
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According to Newton’s third law of motion, when a hammer strikes and exerts force
on a nail, the nail a. | creates a friction with the hammer. | b. | disappears into
the wood. | c. | exerts an equal force back on the
hammer. | d. | moves at a constant speed. | | |
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Completion
Complete each sentence or
statement.
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41.
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The
overall force on an object after all the forces are added together is called the ____________________
force.
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42.
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Unbalanced forces acting on an object produce ____________________
motion.
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43.
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A
measure of an object’s ____________________ is a measure of the object’s
inertia.
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44.
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One
____________________ is the force required to accelerate one kilogram of mass at 1 meter per second
per second.
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45.
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A
person traveling in a car that stops suddenly keeps moving forward due to
____________________.
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46.
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Wet
pavement is more slippery than dry pavement because the force needed to overcome ____________________
friction is less than the force needed to overcome sliding friction.
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47.
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The
downward force acting on an object in free fall is the force of ____________________.
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48.
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A(n)
____________________ is an object that is thrown.
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49.
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When
____________________ equals the force of gravity on a falling object, the object reaches terminal
velocity.
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50.
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The
metric unit that is most often used to describe weight is the ____________________.
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51.
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The
force of gravity between you and Earth is greater than the force of gravity between you and a car
because Earth has more ____________________ than the car.
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52.
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As
the distance between two objects decreases, the gravitational force between them
____________________.
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53.
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According to Newton’s third law of motion, the strength of a reaction force is
____________________ the strength of the action force.
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54.
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If
the action force of a bat striking a ball accelerates the ball in one direction, the reaction force
accelerates the bat in the ____________________ direction.
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55.
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The
momentum of an object is in the same ____________________ as its velocity.
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56.
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The
momentum of a roller skater is not conserved because ____________________ acts on the
skates.
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57.
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During lift-off, the thrust on a rocket is directed
____________________.
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58.
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The
moon is a natural ____________________ of Earth.
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59.
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The
force of gravity is responsible for continuously changing the ____________________ in which a
satellite moves.
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60.
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Friction acts in a direction ____________________ to an object’s direction of
motion.
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