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Newton’s Laws
Practice
1
•
•
•
•
•
The kilogram is a measure of an object’s:
A) weight
B) gravity
C) force
D) mass
2
• Whirl a rock at the end of a string and it
follows a circular path. If the string breaks,
the tendency is of the rock is to:
• A) continue to follow a circular path
• B) follow a straight line path
3
• A sheet of paper can be withdrawn from
under a milk carton without toppling it as
long as the sheet is pulled quickly. This
demonstrates:
• A) gravity tends to hold the carton to the
ground
• B) the carton has inertia
• C) for every action there’s an equal
reaction
4
•
•
•
•
Your weight is:
A) a property of mechanical equilibrium
B) actually your mass
C) the gravitational attraction between
your body and the earth
5
• One object has twice as much mass as
another object, and also has twice as
much:
• A) volume
• B) velocity
• C) inertia
• D) gravitational acceleration
6
• Jupiter has 3 times the gravitational force
of Earth. So on Jupiter, a 100kg object
would have a mass of:
• A) 100kg
• B) 30kg
• C) 300kg
• D) 600kg
7
• An object weighs 20 N on the Earth,
another object weighs 20 N on the moon.
Which object has more mass?
• A) Object on the Earth
• B) Object on the Moon
• C) They have the same mass.
8
•
•
•
•
The law of inertia applies to:
A) objects at rest
B) objects in motion
C) both moving and nonmoving objects
9
• A force is a vector quantity because it has
both:
• A) mass and acceleration
• B) action and reaction counterparts
• C) magnitude and direction
10
• 10kg brick and a 1kg brick are dropped in
a vacuum, the force of gravity on the 10kg
brick is:
• A) zero
• B) 10 times as much as the 1kg brick
• C) the same as the 1kg brick
11
• 10kg brick and a 1kg brick are dropped in
a vacuum, the acceleration due to gravity
on the 10kg brick is:
• A) zero
• B) 10 times as much as the 1kg brick
• C) the same as the 1kg brick
12
• An object is propelled along a straight-line
path. If it’s force were doubled, then it’s
acceleration would:
• A) halve
• B) quadruple
• C) double
• D) stay the same
13
• An object is propelled in a straight-line
path by a force. If the mass of the object
is somehow doubles, it’s acceleration:
• A) halves
• B) quadruples
• C) doubles
• D) stays the same
14
• An object is pulled northward at 20 N and
southward at 15 N. What magnitude of
the net force?
A.
B.
C.
D.
5N
35 N
0N
10 N
15
• A 10N falling object encounters 10N of air
resistance. The magnitude of the net
force is:
• A) 100N
• B) 10N
• C) 0N
• D) Infinite
16
• An apple is held at rest above your head.
The magnitude of the net force of the
apple is:
• A) 10N
• B) 0N
• C) 100N
• D) between 10N and 0N
17
• Which has zero acceleration? An
object_____
• A) at rest
• B) changing its direction
• C) changing its speed
• D) all of these
18
• Whenever the net force on an object is
zero, the acceleration
• A) may be zero
• B) is zero
• C) is not zero
19
• A car has a mass of 3000kg and
accelerates at 2 m/s/s. What is the
magnitude of the force exerted on the car?
A.
B.
C.
D.
1500N
3000N
6000N
2000N
20
• A tow truck exerts a 2 m/s/s acceleration
on a car with a force of 300N. The mass
of the car is
• A) 600 kg
• B) 3000 kg
• C) 150 kg
• D) 1500 kg
21
• A girl pulls a 10kg wagon with a constant
force of 300N. What is the wagon’s
acceleration in m/s/s?
• A) .3
• B) 3000
• C) 30
• D) 1/30
22
• Whenever an object exerts a force on
another object, the second object exerts a
force of the same magnitude but in the
opposite direction.
• A) Always true
• B) Sometimes true
• C) Usually true
23
• A high school student hits a nail with a
hammer. During the collision there is a
force:
• A) On the hammer but not the nail
• B) On the nail but not the hammer
• C) On both hammer and nail
24
•
•
•
•
•
Forces always occur:
A) in singles
B) in pairs
C) in triplets
D) in space
25
• A rocket is able to propel itself in the
vacuum of space by firing its engines. The
force that propels the rocket is:
• A) The exhaust gasses pushing on space
• B) The exhaust gasses heating up the
ship
• C) The exhaust gasses rushing away
from the ship
26
• An archer shoots an arrow. Consider the
action force to be the bowstring pushing
against the arrow. The reaction force is:
• A) air resistance pushing against the arrow
• B) the grip of the archers hand on the bow
• C) the push of the arrow against the
bowstring
• D) none of these
27
• A baseball player bats a ball with a force
of 1000N, the ball exerts a reaction force
against the bat of
• A) 100N
• B) 1000N
• C) A little less than 1000N
• D) Not enough information
28
• As the ball falls, the action force is the
mass of the earth pulling on the ball. The
reaction force is
• A) the ball’s pull on the earth
• B) nonexistent in this case
• C) the ball pushing on the ground
• D) air resistance
29
• A karate chop delivers a blow of 3,000N to
a board that breaks. The force that acts
on the hand is actually:
• A) more than 3000N
• B) less than 3000N
• C) exactly 3000N
• D) depends if the board was oak or ash
30
• Arnold Strongman and Suzy Small pull
hard in opposite directions in a tug of war.
The greatest force on the rope is exerted
by:
• A) Suzy, suprisingly
• B) Arnold, of course
• C) both the same
31
• Which of the following is not an
acceleration?
A. Stopping your bike at an intersection.
B. Riding your bike at a constant speed around
a corner.
C. Slowing your bike down as you reach the top
of the hill.
D. Riding your bike faster as you ride down the
hill.
E. Riding your bike straight down the street at a
constant speed.
32
• ___________ is the pull that all objects
exert on each other.
A.
B.
C.
D.
Resistance
Friction
Inertia
Gravity
33
• At the surface of Jupiter’s moon Io, the
acceleration due to gravity is 2.50 m/s/s. A
watermelon weights 44.0 N at the surface
of the earth. What is the mass on the
earth’s surface?
• What are its mass and weight on the
surface of Io?
34
• What is the net force required to give an
automobile of mass 1600. kg an
acceleration of 4.5 m/s/s?
35
• During a test crash, an air bag inflates to
stop a dummy’s forward motion. The
dummy’s mass is 75.0 kg. If the net force
on the dummy is 825. N toward the rear of
the car, what is the dummy’s acceleration?
36
• A bicycle takes 8.0 seconds to accelerate
at a constant rate from rest to a speed of
4.0 m/s. If the mass of the bicycle and
rider together is 85. kg, what is the net
force acting on the bicycle?
37
• You are waiting in line to use the diving
board at your local pool. While watching
people dive into the pool from the board,
you realize that using a diving board to
spring into the air before a dive is a good
example of Newton’s third law of motion.
Explain how a diving board illustrates
Newton’s 3rd law.
38
• If bullets are fired from an airplane in the
direction of its motion . . .
A. the speed of the airplane will increase.
B. the speed of the airplane will decrease.
C. there will be no change in the speed of the
airplane.
D. the speed will change but the velocity will
remain the same.
39
• Which exerts more force, the Earth pulling
on the moon or the moon pulling on the
Earth? Explain.
40
• When a heavy football player and a light
one run into each other, which player hits
the other with more force? Explain.
Which one is hurt more by the collision?
Explain.
41
• Equilibrium is the state of motion where
A. All forces on an object are balanced.
B. An object can be accelerating or sitting at
rest.
C. Both A and B
D. Neither A nor B
42
• According to Newton’s second law of
motion, if the net force acting on the object
increases while the mass of the object
remains constant, what happens to the
acceleration?
A.
B.
C.
D.
Acceleration decreases
Acceleration increases
Acceleration remains the same
Acceleration is independent of mass
43
• In order to start a grocery cart in motion,
you must exert 72.0 Newtons of force on
the handle. The mass of the grocery cart
is 61.0 kg. How much force does the cart
exert on your hand as you accelerate it
forward?
A.
B.
C.
D.
4400 N
1.2 N
72.0 N
0N
44
• How much does a 9.8 kg pail of water
weigh?
A.
B.
C.
D.
9.80 kg
96.0 N
9.80 N
96.0 kg
45
• When an object is not in equilibrium, what
kind of motion can it have?
A.
B.
C.
D.
Circular
Accelerating
Decelerating
All of the above
46
• A helicopter weighs 12,800 N, how much
force must its rotors exert on the air in
order to start it rising into the air from its
landing pad?
47
• A 2 kg box sits on a 3 kg box which sits on
a 5 kg box. The 5 kg box rests on a table
top. What is the normal force exerted on
the 5 kg box by the table top?
A.
B.
C.
D.
19.6 N
29.4 N
49 N
98 N
48
• A 2 kg box sits on a 3 kg box which sits on
a 5 kg box. The 5 kg box rests on a table
top. What is the normal force exerted by
the 5 kg box on the 3 kg box?
A.
B.
C.
D.
19.6 N
29.4 N
49 N
98 N
49
• A car pulls on a rope tied to a tree with a
force of 1000 N. Which of the following is
not true?
A. The rope pulls on the tree with a force of
1000 newtons.
B. The tree pulls on the rope with a force of
1000 newtons.
C. The tension in the rope is 2000 newtons.
D. The tension in the rope is 1000 newtons.
50
• A free-body diagram of a ball in free fall would show
A. a downward arrow to represent the force of air
resistance.
B. only a downward arrow to represent the force of
gravity.
C. a downward arrow to represent the force of gravity
and an upward arrow to represent the force of air
resistance.
D. an upward arrow to represent the force of gravity
and a downward arrow to represent the force of air
resistance.
51
• Which of the following is the tendency of
an object to maintain its state of motion?
A.
B.
C.
D.
Acceleration
Inertia
Force
Velocity
52
• If a nonzero net force is acting on an
object, then the object is definitely
A.
B.
C.
D.
at rest.
moving with a constant velocity.
being accelerated.
losing mass.
53
• According to Newton’s 2nd law, when the same force is applied to
two objects of different masses,
A. the object with greater mass will experience a great
acceleration and the object with less mass will experience an
even greater acceleration.
B. the object with greater mass will experience a smaller
acceleration and the object with less mass will experience a
greater acceleration.
C. the object with greater mass will experience a greater
acceleration and the object with less mass will experience a
smaller acceleration.
D. the object with greater mass will experience a smaller
acceleration and the object with less mass will experience an
even smaller acceleration.
54
• A hammer drives a nail into a piece of
wood. Identify an action-reaction pair.
A. The nail exerts a force on the hammer; the
hammer exerts a force on the wood.
B. The hammer exerts a force on the nail; the
nail exerts a force on the wood.
C. The hammer exerts a force on the nail; the
nail exerts a force on the hammer.
D. The hammer exerts a force on the nail; the
hammer exerts a force on the wood.
55
• When a car is moving, what happens to
the velocity and acceleration of the car if
the air resistance becomes equal to the
force acting in the opposite direction?
56
• A force of 10. N applied to a given mass
accelerates is at 1.0 m/s/s. The same
force applied to a mass one-half as great
would produce an acceleration of
A.
B.
C.
D.
1.0 m/s/s
2.0 m/s/s
0.50 m/s/s
4.0 m/s/s
57
• A certain net force causes a 10. kg mass
to accelerate at 20. m/s/s. The same force
will cause a 5.0 kg mass to accelerate at
A.
B.
C.
D.
9.8 m/s/s
10. m/s/s
25. m/s/s
40. m/s/s
58
• If the sum of all the forces acting on a car
is zero, the car
A. must be at rest.
B. must be moving at a constant speed.
C. may be at rest or moving at a constant
speed.
D. must be accelerating.
59
• Which of the following is equal to one
Newton?
A.
B.
C.
D.
Kg m/s
Kg m
Kg m/s/s
Kg/m/s/s
60
• The weight of an apple to closest to
A.
B.
C.
D.
1N
9.8 N
19.6 N
980 N
61
• On the surface of a distant planet a 5 kg
mass weighs 20 N. What is the
acceleration due to gravity there?
A.
B.
C.
D.
0.25 m/s/s
1 m/s/s
4 m/s/s
15 m/s/s
62
• If we know an object is moving at constant
velocity, we may assume
A.
B.
C.
D.
E.
the net force acting on the object is zero.
there are no forces acting on the object.
the object is accelerating.
the object is losing mass.
the net force acting on the object isn’t zero.
63
• A 7.0 kg bowling ball experiences a net
force of 5.0 N. What will be its
acceleration?
A.
B.
C.
D.
E.
35 m/s/s
7.0 m/s/s
5.0 m/s/s
0.71 m/s/s
0.52 m/s/s
64
• Rita accelerates a 0.40 kg ball from rest to
9.0 m/s during the 0.15 seconds in which
her foot is in contact with the ball. What
average force does she apply to the ball
during the kick?
A.
B.
C.
D.
E.
48 N
72 N
24 N
60 N
76 N
65
• As a 3.0 kg bucket is being lowered into a
10 meter deep well, starting from the top,
the tension in the rope is 9.8 N. The
acceleration of the bucket will be
A.
B.
C.
D.
E.
6.5 m/s/s downward
9.8 m/s/s downward
zero
3.3 m/s/s upward
6.5 m/s/s upward
66
• A karate master strikes a board with an initial velocity of 10.0
m/s, decreasing to 1.0 m/s as his hand passes through the
board. If the time of contact with the board is 0.002 seconds
and the mass of the coordinated hand and arm is 1.0 kg, what
is the force exerted on the board?
A. -1000 N
B. 1800 N
C. -2700 N
D. -4500 N
E. 4500 N
67
• In which case would you have the largest
mass of gold? If your chunk of gold
weighed 1 N on the
A. moon.
B. Earth.
C. planet Jupiter.
68
• An object is propelled along a straight-line
path by a force. If the net force were
doubled, the object’s acceleration would
be
A.
B.
C.
D.
E.
half as much.
twice as much.
the same.
four times as much.
None of these
69
• An object is propelled along a straight line
path in space by a force. If the mass of
the object somehow becomes twice as
much, its acceleration
A.
B.
C.
D.
E.
quadruples.
doubles.
stays the same.
halves.
None of these
70
• The force of friction on a sliding object is
10 newtons. The applied force needed to
maintain a constant velocity is
A. more than 10 N.
B. less than 10 N.
C. 10 N.
71
• An apple at rest weighs 1 N. The net force
on the apple when it is in free fall is
A.
B.
C.
D.
E.
0 N.
0.1 N
1N
9.8 N
None of these
72
• An object following a straight line path at
constant speed
A. has a net force acting upon it in the direction
of motion.
B. has zero acceleration.
C. has no forces acting on it.
D. both B & C
E. None of these.
73
• A rocket becomes progressively easier to
accelerate as it travels upward from the
ground mainly because
A. gravity becomes weaker with increased
distance.
B. the applied force on the rocket increases as
burning of fuel progresses.
C. the mass of the rocket decreases as fuel is
burned.
74
• A rock is thrown vertically into the air. At
the top of its path, its acceleration in
meters per second per second is
A.
B.
C.
D.
zero.
9.8.
between 0 and 9.8.
greater than 9.8.
75
• Suppose a particle is being accelerated through space
by a 10 N force. Suddenly the particle encounters a
second force of 10 N in the opposite direction from the
first force. The particle with both forces acting on it
A. is brought to a rapid halt.
B. decelerates gradually to a halt.
C. continues at the speed it had when it encountered
the second force.
D. theoretically tends to accelerate toward the speed of
light.
E. None of these
76
• A 1 kg rock that weighs 9.8 N is thrown
straight upward at 20 m/s. Neglecting air
resistance, the net force that acts on it
when it is half way to the top of its path is
A. less than 9.8 N.
B. 9.8 N.
C. more than 9.8 N.
77
• If an object of constant mass experiences
a constant net force, it will have a constant
A.
B.
C.
D.
velocity.
speed.
acceleration.
position.
78
• If less horizontal force is applied to a
sliding object than is needed to maintain
constant velocity
A. the object accelerates in the direction of the
applied force.
B. the friction force increases.
C. the object eventually slides to a stop.
D. None of these
79. A stoplight 20 m to the west turns yellow. Your car is
traveling west at 12 m/s. You hit the brakes and slows down
at a rate of 6.0 m/s2. Your car stops before it reaches the
stoplight (which is considered to be at “zero”).
A student in a physics class made a picture of the situation
but did not include the signs of the variables.
x
to = 0 s
xo = __ 20 m
vo = __ 12 m/s
a = __ 6.0 m/s2
What are the signs of the three missing variables?
1
2
3
4
5
xo
+
+
+
+
–
vo
–
–
+
+
–
a
–
+
–
+
+
80. A stoplight 20 m to the west turns yellow. Your car is
traveling west at 12 m/s. You hit the brakes and slow down at
a rate of 6.0 m/s2. Your car stops before it reaches the
stoplight (which is considered to be at “zero”).
A student in a physics class made a picture of this.
x
to = 0 s
xo = + 20 m
vo = – 12 m/s
a = – 6.0 m/s2
Which of the following is labeled wrong?
1
2
3
4
5
xo
vo
a
a & vo
all of the values are correct
81. The motion of a car is represented with the motion
diagram below.
vfinal
vinitial
a
x
Which graph best matches the motion diagram?
1
2v
v
t
3
v
t
t
t
4v
5 No graph represents
the motion correctly
82. A stoplight 20 m to the west turns yellow. Your car is
traveling west at 12 m/s. You hit the brakes and slows down
at a rate of 6.0 m/s2. Your car stops before it reaches the
stoplight (which is considered to be at “zero”).
Which graph is the best representation of the car’s
motion?
1
2x
x
3
x
t
t
4
x
t
t
5 No graph represents the
motion correctly
83. A bicycle is moving on the road. Its motion is described
by the graph below.
t
v
Below is a mathematical description of the same motion.
What should the signs of vo and a be to be consistent with
the above graphical description?
1
2
3
4
vo
+
+
–
–
a
–
+
+
–
84. Alan sees the following three diagrams
next to each other in his physics book.
v
x
a
t
A
t
B
t
C
Are these three diagrams consistent with each other?
1. Yes, all three diagrams are consistent.
2. No, Diagram A is not consistent with the other two.
3. No, Diagram B is not consistent with the other two.
4. No, Diagram C is not consistent with the other two.
5. None of the diagrams are consistent.