Question 1

Are there any kinds of situations in which the momentum of a moving system is not conserved?

Accepted Answer

A)  No, because the momentum of any system is always conserved. 
B)  Yes, if there is friction acting between different parts of the system. 
C)  Yes, if some of the parts of the system collide with each other. 
D)  Yes, if any part of the system is acted upon by forces external to the system. 
E)  No, because the law of inertia demands that any moving system must keep moving. 
A)  No, because the momentum of any system is always conserved. 
B)  Yes, if there is friction acting between different parts of the system. 
C)  Yes, if some of the parts of the system collide with each other. 
D)  Yes, if any part of the system is acted upon by forces external to the system. 
E)  No, because the law of inertia demands that any moving system must keep moving.

Question 2

You hold a 5- newton rock motionless in your hand. Regarding the forces on this rock,

Accepted Answer

A)  there are no forces of any kind acting on the rock, because it is not moving. 
B)  the downward force of gravity is balanced by the upward force of air resistance. 
C)  the net force on the rock is 5 newtons, directed upward. 
D)  the net force on the rock is 5 newtons, directed downward. 
E)  the net force on the rock is zero. 
A)  there are no forces of any kind acting on the rock, because it is not moving. 
B)  the downward force of gravity is balanced by the upward force of air resistance. 
C)  the net force on the rock is 5 newtons, directed upward. 
D)  the net force on the rock is 5 newtons, directed downward. 
E)  the net force on the rock is zero.

Question 3

A certain grapefruit on Earth has a mass of one kilogram and a weight of one newton. When the grapefruit is on the moon its mass is

Accepted Answer

A)  one kilogram. 
B)  less than ten newtons. 
C)  ten newtons. 
D)  less than one kilogram. 
A)  one kilogram. 
B)  less than ten newtons. 
C)  ten newtons. 
D)  less than one kilogram.

Question 4

Mary pushes horizontally on a large, heavy table which is standing alone in the middle of a room, and notes that the table does not move despite the fact that she is pushing on it (see the figure). Why doesn't the table move?

Accepted Answer

A)  Very massive objects, such as the table, are difficult to set into motion because of their large inertia. 
B)  The table pushes back on Mary with a force that is even larger than Mary's pushing force. 
C)  The force of gravity pulls downward on the table, and this force cancels the pushing force. 
D)  A frictional force is also exerted by the floor on the table, and this force is equal and opposite to the pushing force. 
E)  The table exerts a force on Mary, and this force is equal and opposite to the pushing force. 
A)  Very massive objects, such as the table, are difficult to set into motion because of their large inertia. 
B)  The table pushes back on Mary with a force that is even larger than Mary's pushing force. 
C)  The force of gravity pulls downward on the table, and this force cancels the pushing force. 
D)  A frictional force is also exerted by the floor on the table, and this force is equal and opposite to the pushing force. 
E)  The table exerts a force on Mary, and this force is equal and opposite to the pushing force.

Question 5

One- third as much net force is exerted on object A as on object B. The two objects have the same mass. How do their accelerations compare?

Accepted Answer

A)  Object A has three times as much acceleration as object B. 
B)  Object A has one- sixth as much acceleration as object B. 
C)  Object A has one- third as much acceleration as object B. 
D)  They both have the same acceleration. 
E)  It is impossible to answer this without further information about the two objects. 
A)  Object A has three times as much acceleration as object B. 
B)  Object A has one- sixth as much acceleration as object B. 
C)  Object A has one- third as much acceleration as object B. 
D)  They both have the same acceleration. 
E)  It is impossible to answer this without further information about the two objects.

Question 6

You throw a ball straight upward. While it is moving upward, the net force on the ball is

Accepted Answer

A)  zero. 
B)  in the downward direction. 
C)  in the horizontal direction. 
D)  in the upward direction. 
E)  directed oppositely to the acceleration. 
A)  zero. 
B)  in the downward direction. 
C)  in the horizontal direction. 
D)  in the upward direction. 
E)  directed oppositely to the acceleration.

Question 7

Suppose we subject a golf ball and a more massive lead ball to identical net forces. Then, compared to the golf ball, the lead ball must have

Accepted Answer

A)  a larger acceleration. 
B)  a smaller acceleration. 
C)  a larger speed. 
D)  a smaller speed. 
E)  None of the above answers is necessarily true. 
A)  a larger acceleration. 
B)  a smaller acceleration. 
C)  a larger speed. 
D)  a smaller speed. 
E)  None of the above answers is necessarily true.

Question 8

The basic physical principal principle that explains the operation of rocket engines is

Accepted Answer

A)  the law of force pairs. 
B)  the law of inertia. 
C)  the atomic hypothesis. 
D)  Galileo's principle of falling. 
E)  Actually, rockets are unexplainable. 
A)  the law of force pairs. 
B)  the law of inertia. 
C)  the atomic hypothesis. 
D)  Galileo's principle of falling. 
E)  Actually, rockets are unexplainable.

Question 9

A stationary firecracker explodes, breaking into two parts of equal mass. One part is moving north at 20 m/s. The velocity of the other part is

Accepted Answer

A)  20 m/s with a direction that's impossible to predict without more information. 
B)  also northward at 20 m/s. 
C)  zero. 
D)  southward at 20 m/s. 
E)  impossible to predict without more information. 
A)  20 m/s with a direction that's impossible to predict without more information. 
B)  also northward at 20 m/s. 
C)  zero. 
D)  southward at 20 m/s. 
E)  impossible to predict without more information.

Question 10

A block of wood is given a brief push and then allowed to slide [without further pushing] along a table top, slowing down as it moves toward the east. As the block slides,

Accepted Answer

A)  its acceleration is toward the east. 
B)  its acceleration is toward the west. 
C)  the net force on it is zero. 
D)  it has no acceleration. 
E)  its velocity is toward the west. 
A)  its acceleration is toward the east. 
B)  its acceleration is toward the west. 
C)  the net force on it is zero. 
D)  it has no acceleration. 
E)  its velocity is toward the west.

Question 11

A rocket taking off straight upward develops a thrust of 10,000 newtons. The rocket weighs 2,000 newtons. The net force on the rocket, neglecting air resistance, is

Accepted Answer

A)  8,000 newtons. 
B)  10,000 newtons. 
C)  12, 000 newtons. 
D)  2,000 newtons. 
E)  zero. 
A)  8,000 newtons. 
B)  10,000 newtons. 
C)  12, 000 newtons. 
D)  2,000 newtons. 
E)  zero.

Question 12

Which of the following principles explains why guns recoil?

Accepted Answer

A)  The law of inertia. 
B)  Conservation of momentum. 
C)  Newton's law of motion. 
D)  Conservation of energy. 
E)  None of the above. 
A)  The law of inertia. 
B)  Conservation of momentum. 
C)  Newton's law of motion. 
D)  Conservation of energy. 
E)  None of the above.

Are there any kinds of situations in which the momentum of a moving system is not conserved?

You hold a 5- newton rock motionless in your hand. Regarding the forces on this rock,

A certain grapefruit on Earth has a mass of one kilogram and a weight of one newton. When the grapefruit is on the moon its mass is

Mary pushes horizontally on a large, heavy table which is standing alone in the middle of a room, and notes that the table does not move despite the fact that she is pushing on it (see the figure). Why doesn't the table move?

One- third as much net force is exerted on object A as on object B. The two objects have the same mass. How do their accelerations compare?

You throw a ball straight upward. While it is moving upward, the net force on the ball is

Suppose we subject a golf ball and a more massive lead ball to identical net forces. Then, compared to the golf ball, the lead ball must have

The basic physical principal principle that explains the operation of rocket engines is

A stationary firecracker explodes, breaking into two parts of equal mass. One part is moving north at 20 m/s. The velocity of the other part is

A block of wood is given a brief push and then allowed to slide [without further pushing] along a table top, slowing down as it moves toward the east. As the block slides,

A rocket taking off straight upward develops a thrust of 10,000 newtons. The rocket weighs 2,000 newtons. The net force on the rocket, neglecting air resistance, is

Which of the following principles explains why guns recoil?

The Way of Science: Experience and Reason

Atoms: the Nature of Things

How Things Move: Galileo Asks the Right Questions

Newtons Universe

Conservation of Energy: You Cant Get Ahead

Second Law of Thermodynamics: and You Cant Even Break Even

Light and Electromagnetism

Electromagnetism Radiation and Global Climate Change

The Special Theory of Relativity

The General Theory of Relativity and the New Cosmology

The Quantum Idea

The Quantum Universe

The Nucleus and Radioactivity: an New Force

Fusion and Fission: and a New Energy

The Energy Challenge

Quantum Fields: Relativity Meets the Quantum

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Exam 4: Why Things Move As They Do

Are there any kinds of situations in which the momentum of a moving system is not conserved?

You hold a 5- newton rock motionless in your hand. Regarding the forces on this rock,

A certain grapefruit on Earth has a mass of one kilogram and a weight of one newton. When the grapefruit is on the moon its mass is

Mary pushes horizontally on a large, heavy table which is standing alone in the middle of a room, and notes that the table does not move despite the fact that she is pushing on it (see the figure). Why doesn't the table move?

One- third as much net force is exerted on object A as on object B. The two objects have the same mass. How do their accelerations compare?

You throw a ball straight upward. While it is moving upward, the net force on the ball is

Suppose we subject a golf ball and a more massive lead ball to identical net forces. Then, compared to the golf ball, the lead ball must have

The basic physical principal principle that explains the operation of rocket engines is

A stationary firecracker explodes, breaking into two parts of equal mass. One part is moving north at 20 m/s. The velocity of the other part is

A block of wood is given a brief push and then allowed to slide [without further pushing] along a table top, slowing down as it moves toward the east. As the block slides,

A rocket taking off straight upward develops a thrust of 10,000 newtons. The rocket weighs 2,000 newtons. The net force on the rocket, neglecting air resistance, is

Which of the following principles explains why guns recoil?

The Way of Science: Experience and Reason

Atoms: the Nature of Things

How Things Move: Galileo Asks the Right Questions

Newtons Universe

Conservation of Energy: You Cant Get Ahead

Second Law of Thermodynamics: and You Cant Even Break Even

Light and Electromagnetism

Electromagnetism Radiation and Global Climate Change

The Special Theory of Relativity

The General Theory of Relativity and the New Cosmology

The Quantum Idea

The Quantum Universe

The Nucleus and Radioactivity: an New Force

Fusion and Fission: and a New Energy

The Energy Challenge

Quantum Fields: Relativity Meets the Quantum

Filters