Modified True/False
Indicate
whether the statement is true or false. If false, change the identified word or phrase to make
the statement true.
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1.
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The strength of gravity as measured on the surface of Earth is 9.8 newtons
per kilogram. _________________________
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2.
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To calculate the weight of an object, the strength of gravity is
multiplied by the mass of the object. _________________________
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3.
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The friction that can be measured when an object is sliding over a surface is
static friction. _________________________
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Multiple Choice
Identify the
choice that best completes the statement or answers the question.
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4.
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Friction between two surfaces may reduced by all of the following methods
EXCEPT:
a. | putting liquid such as oil between the surfaces. | b. | pushing the two
surfaces together with a greater force. | c. | separating the two surfaces with a cushion of
air. | d. | using ball bearings between the two surfaces changing sliding motion to rolling
motion. |
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5.
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A force that always tends to slow the motion of an object on a surface
is:
a. | mass. | b. | weight. | c. | friction. | d. | inertia. |
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6.
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The force of gravity on an object is called:
a. | mass. | b. | inertia. | c. | weight. | d. | volume. |
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7.
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A unit of measurement used to indicate force is the:
a. | newton. | b. | gram. | c. | meter. | d. | scalar. |
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8.
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Jane’s weight on the moon would be less than her weight on Earth
because:
a. | she has less mass on the moon than on Earth. | b. | there is no
atmosphere on the moon. | c. | the moon has less mass than
Earth. | d. | the radius of the moon is greater than the radius of
Earth. |
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9.
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The friction force acting on an object will be greatest if the object is:
a. | not moving. | b. | moving with increasing
speed. | c. | moving with decreasing speed. | d. | moving with constant
speed. |
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10.
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A small boy pushes a chair across a waxed floor. A friend sits down in the
chair, and the boy pushes the chair across the floor again. How does the weight of the friend in the
chair affect the friction between the chair and the floor?
a. | Friction stays the same because the chair is moving. | b. | Friction is
decreased because inertia increases. | c. | Friction increases because the floor and chair
are pushed together harder. | d. | Friction stays the same because the forces act
in different directions. |
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11.
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Frank’s mass has been measured as 60 kilograms. On the moon, his mass
would be about:
a. | 10 kg | b. | 60 kg | c. | 100
kg | d. | 600 kg |
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12.
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Luka pushes a box across the floor in the direction shown by the arrow in the
diagram below:  The direction of the friction force
acting on the box is: a. | up. | b. | down. | c. | right. | d. | left. |
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13.
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If the net force acting on an object is zero, the speed of the object
must:
a. | increase. | b. | decrease. | c. | remain the
same. | d. | be zero. |
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14.
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The relationship between the weight and mass of an object is given by the
formula, W = mg, where W = weight, m = mass and g = the
strength of gravity. On the moon, the strength of gravity is 1.6 N/kg. A 22-kilogram rock on the
moon would weigh:
a. | 2.2 N | b. | 14 N | c. | 35
N | d. | 220 N |
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15.
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At Earth’s surface a 1.0 kilogram has a weight of 9.8 newtons. 78.4
newtons resting on the ground has a mass of:
a. | 1.0 kg | b. | 8.0 kg | c. | 68.6
kg | d. | 88.2 kg |
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16.
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The term that best describes the situation for ALL bodies on which the net force
is zero is:
a. | weightless. | b. | motionless. | c. | accelerating. | d. | equilibrium. |
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Completion
Complete each
statement.
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Select the correct term to complete each sentence. There are extra terms in
the list.| equilibrium | net | free-body | | mass | gravity | accelerating | | friction | vector | gravity | | | |
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17.
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The force of gravity on an object is called ____________________.
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18.
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The force exerted by the surface on which an object is resting is the
____________________ force.
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19.
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A force that resists the motion of objects or surfaces as they move over one
another is called ____________________.
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20.
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You would have the same ____________________ if you were on Earth, the moon, or
Jupiter.
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Short Answer
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21.
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List three methods by which frictional forces may be reduced between
surfaces.
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22.
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Name the units of measurement used to identify each of the following
quantities:
a. Strength of gravity
b. Mass of an object
c. Weight of an object
d. Force
exerted on an object
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Problem
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23.
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Yuji, a surfer, weighs 635 newtons on his favorite beach in California.
Calculate what Yuji’s mass would be on the surface of the moon.
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24.
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An astronaut weighs 825 newtons on Earth’s surface. Since the strength of
gravity on the moon is less than on Earth, the astronaut weighs less on the moon than on Earth.
Calculate the astronaut’s weight on the moon if the strength of gravity on the moon is 1.6
newtons per kilogram.
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Essay
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25.
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When pushing on an object, it is generally easier to keep the object moving than
it is to start the object moving. Explain why this is so including the terms static and
kinetic friction in your explanation.
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26.
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An empty wagon rolls easily, but a loaded wagon is more difficult to roll. Using
your knowledge of friction force and weight, explain why this is so.
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27.
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Friction can be useful. List four ways and give a brief explanation of
how it is useful.
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