Question 1

A horse pulls a cart along a flat road. Consider the following four forces that arise in this situation.
(1) the force of the horse pulling on the cart
(2) the force of the cart pulling on the horse
(3) the force of the horse pushing on the road
(4) the force of the road pushing on the horse
-Which two forces form an "action-reaction" pair that obeys Newton's third law?
A)1 and 4
B)1 and 3
C)2 and 4
D)3 and 4
E)2 and 3

Accepted Answer

The answer of A horse pulls a cart along a...

Question 2

-Which one of the following statements concerning this situation is true?
A)The spacecraft does not move, but the astronaut moves to the right with a constant speed.
B)The astronaut stops moving after he stops pushing on the spacecraft.
C)The force exerted on the astronaut is larger than the force exerted on the spacecraft.
D)The force exerted on the spacecraft is larger than the force exerted on the astronaut.
E)The velocity of the astronaut increases while he is pushing on the spacecraft.

Accepted Answer

According to Newton's third law, the forces exerted by the astronaut and the spacecraft on each other are equal in magnitude and opposite in direction. While the astronaut is pushing on the spacecraft, he experiences an acceleration, causing his velocity to increase.

Question 3

Two point masses m and M are separated by a distance d. If the distance between the masses is increased to 3d, how does the gravitational force between them change?
A)The force will be one-third as great.
B)The force will be one-ninth as great.
C)The force will be three times as great.
D)The force will be nine times as great.
E)It is impossible to determine without knowing the numerical values of m, M, and d.

Accepted Answer

The gravitational force between two masses is inversely proportional to the square of the distance between them. When the distance between the masses is increased from d to 3d, the new distance is nine times the original distance. Therefore, the new force will be (1/9)^2 = 1/81 times the original force, which is equivalent to saying that the force will be one-ninth as great.

Question 4

A rock is thrown straight up from the earth's surface. Which one of the following statements concerning the net force acting on the rock at the top of its path is true?
A)The net force is equal to the weight of the rock.
B)The net force is instantaneously equal to zero newtons.
C)The direction of the net force changes from up to down.
D)The net force is greater than the weight of the rock.
E)The net force is less than the weight of the rock, but greater than zero newtons.

Accepted Answer

At the top of its path, the only force acting on the rock is gravity, so the net force is equal to the weight of the rock.

Question 5

A marble is dropped straight down from a distance h above the floor. Let F_m = the magnitude of the gravitational force on the marble due to the earth; F_e= the magnitude of the gravitational force on the earth due to the marble; A_m= the magnitude of the acceleration of the marble toward the earth; A_e= the magnitude of the acceleration of the earth toward the marble. Which set of conditions is true as the marble falls toward the earth? Neglect any effects of air resistance. A)F_m = F_e and a_m < a_e B)F_m < F_e and a_m > a_e C)F_m < F_e and a_m = a_e D)F_m > F_e and a_m = a_e E)F_m = F_e and a_m > a_e

Accepted Answer

According to Newton's third law, the forces are equal in magnitude (F_m = F_e). However, due to the large mass of the Earth compared to the marble, the acceleration of the marble (a_m) is much greater than the acceleration of the Earth (a_e).

Question 6

A physics student in a hot air balloon ascends vertically at constant speed. Consider the following four forces present in this situation: 1= the weight of the hot air balloon 3= the force of the student pulling on the earth 2= the weight of the student 4= the force of the hot air balloon pulling on the student -Which two forces form an "action-reaction" pair that obeys Newton's third law? A) ₁ and ₂ B) ₂ and ₃ C) ₁ and ₃ D) ₂ and ₄ E) ₃ and ₄

Accepted Answer

The answer of A physics student in a hot air...

Question 7

An astronaut orbits the earth in a space capsule whose height above the earth is equal to the earth's radius. How does the mass of the astronaut in the capsule compare to her mass on the earth?
A)Her mass is equal to her mass on earth.
B)Her mass is approximately equal to one-fourth her mass on earth.
C)Her mass is approximately equal to one-half of her mass on earth.
D)Her mass is approximately equal to one-third of her mass on earth.
E)Her mass is approximately equal to one-sixteenth her mass on earth.

Accepted Answer

The astronaut's mass is the same in orbit as it is on Earth. Mass is a measure of the amount of matter in an object, and it does not change with location.

Question 8

What is the weight of a 2.50-kg bag of sand on the surface of the earth?
A)2.50 N
B)9.80 N
C)24.5 N
D)49.0 N
E)98.0 N

Accepted Answer

The weight of an object is calculated by multiplying its mass by the acceleration due to gravity (9.8 m/s² on Earth). So, 2.50 kg * 9.8 m/s² = 24.5 N.

Question 9

Which one of the following statements concerning the two "gravitational constants" G, the universal gravitational constant, and g the magnitude of the acceleration due to gravity is true?
A)The values of g and G depend on location.
B)The values of g and G do not depend on location.
C)The value of G is the same everywhere in the universe, but the value of g is not.
D)The value of g is the same everywhere in the universe, but the value of G is not.
E)The values of g and G are equal on the surface of any planet, but in general, G varies with location in the universe.

Accepted Answer

The value of G is the same everywhere in the universe, but the value of g is not.

Question 10

Two satellites of different masses are in the same circular orbit around the earth. Which one of the following statements is true concerning the magnitude of the gravitational force that acts on each of them?
A)The magnitude of the gravitational force is zero newtons for both satellites.
B)The magnitude of the gravitational force is the same for both satellites, but not zero newtons.
C)The magnitude of the gravitational force is zero newtons for one, but not for the other.
D)The magnitude of the gravitational force depends on their masses.
E)The magnitude of the gravitational force varies from point to point in their orbits.

Accepted Answer

The gravitational force on each satellite depends on its mass, as given by Newton's law of universal gravitation.

Question 11

Consider the following forces. (1) frictional (2) gravitational (3) tension (4) strong nuclear (5) normal (6) electroweak
Which of the forces listed are considered fundamental forces?
A)1, 2, and 4
B)1, 2, 3, and 5
C)1, 3, and 5
D)2, 4, and 6
E)2, 3, 4, and 6

Accepted Answer

The only fundamental forces in the list are gravitational, strong nuclear, and electroweak forces. This means that they cannot be explained by other forces and are considered to be the basic building blocks of all other forces. Frictional, tension, and normal forces are all macroscopic forces that can be explained by electromagnetic forces, while strong nuclear and electroweak forces are only observed at the subatomic level. Therefore, the forces listed in choice D are the only ones that include all the fundamental forces.

Question 12

Which one of the following statements best explains why the weight of an object of mass m is different on Mars than it is on the Earth?
A)The mass of Mars is different from that of Earth.
B)The masses and radii of Mars and Earth are not the same.
C)The mass m is further from the Earth's center when it is on Mars.
D)The constant G is different on Mars.
E)The mass m will be different on Mars.

Accepted Answer

Weight is the force of gravity acting on an object, which is dependent on both the object's mass and the gravitational pull of the planet. The gravitational pull depends on the mass and radius of the planet, and since Mars and Earth have different masses and radii, the weight of an object with the same mass will be different on each planet.

Question 13

A horse pulls a cart along a flat road. Consider the following four forces that arise in this situation.
(1) the force of the horse pulling on the cart
(2) the force of the cart pulling on the horse
(3) the force of the horse pushing on the road
(4) the force of the road pushing on the horse
-Suppose that the horse and cart have started from rest; and as time goes on, their speed increases in the same direction. Which one of the following conclusions is correct concerning the magnitudes of the forces mentioned above?
A)Force 1 exceeds force 2.
B)Force 2 is less than force 3.
C)Force 2 exceeds force 4.
D)Force 3 exceeds force 4.
E)Forces 1 and 2 cannot have equal magnitudes.

Accepted Answer

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Question 14

-The book has an acceleration of 0 m/s². Which pair of forces, excluding "action-reaction" pairs, must be equal in magnitude and opposite in direction? A)1 and 2 B)1 and 3 C)1 and 4 D)2 and 3 E)2 and 4

Accepted Answer

The book has an acceleration of 0 m/s², so the net force on the book is zero. This means that the sum of the forces in the x-direction must be equal to zero, and the sum of the forces in the y-direction must be equal to zero.Force 1 is in the x-direction and is positive, so force 2 must be in the x-direction and negative in order to cancel out force 1.

Question 15

An astronaut orbits the earth in a space capsule whose height above the earth is equal to the earth's radius. How does the weight of the astronaut in the capsule compare to her weight on the earth?
A)Her weight is equal to zero newtons.
B)Her weight is approximately equal to one-fourth her weight on earth.
C)Her weight is approximately equal to one-half of her weight on earth.
D)Her weight is approximately equal to one-third of her weight on earth.
E)Her weight is approximately equal to one-sixteenth her weight on earth.

Accepted Answer

When an object is at a height equal to the radius of the earth, the force of gravity acting on it is only one-fourth of the force of gravity acting on it at the surface of the earth. This means that the weight of the astronaut in the capsule is only one-fourth of her weight on earth. Therefore, the best choice is B.

Question 16

-Determine the magnitude of the acceleration of the spacecraft. A)51.4 m/s² B)0.36 m/s² C)2.5 × 10^-³ m/s² D)7.0 × 10^-³ m/s² E)3.97 × 10^-⁴ m/s²

Accepted Answer

The answer of 
-Determine the magnitude of the acceleration of...

Question 17

Two point masses m and M are separated by a distance d. If the separation d remains fixed and the masses are increased to the values 3m and 3M respectively, how does the gravitational force between them change?
A)The force will be one-third as great.
B)The force will be one-ninth as great.
C)The force will be three times as great.
D)The force will be nine times as great.
E)It is impossible to determine without knowing the numerical values of m, M, and d.

Accepted Answer

According to the law of gravitation, the force is directly proportional to the product of masses and inversely proportional to the square of the distance between them. So, when the masses are increased to 3m and 3M, the force becomes (3m) x (3M) x G / d^2, where G is the gravitational constant. This can be simplified as 9(m x M x G / d^2), which is nine times the original force. Therefore, the correct answer is D.

Question 18

A 2.00-kg projectile is fired at an angle of 20.0°. What is the magnitude of the force exerted on the projectile when it is at the highest position in its trajectory? Neglect any effects of air resistance.
A)19.6 N
B)14.7 N
C)9.80 N
D)4.90 N
E)0 N

Accepted Answer

The answer of A 2.00-kg projectile is fired at an...

Question 19

A physics student in a hot air balloon ascends vertically at constant speed. Consider the following four forces present in this situation: 1= the weight of the hot air balloon 3= the force of the student pulling on the earth 2= the weight of the student 4= the force of the hot air balloon pulling on the student -Which one of the following relationships concerning the forces or their magnitudes is true? A)F₄ > F₂ B)F₁< F₂ C)F₄> F₁ D) ₂ = - ₄ E) ₃ = - ₄

Accepted Answer

The answer of A physics student in a hot air...

Question 20

-Which two forces form an "action-reaction" pair that obeys Newton's third law?
A)1 and 2
B)1 and 3
C)1 and 4
D)2 and 4
E)3 and 4

Accepted Answer

The answer of 
-Which two forces form an "action-reaction" pair...

Quiz 4: Forces and Newtons Laws of Motion

-Which one of the following statements concerning this situation is true?

Two point masses m and M are separated by a distance d. If the distance between the masses is increased to 3d, how does the gravitational force between them change?

A rock is thrown straight up from the earth's surface. Which one of the following statements concerning the net force acting on the rock at the top of its path is true?

An astronaut orbits the earth in a space capsule whose height above the earth is equal to the earth's radius. How does the mass of the astronaut in the capsule compare to her mass on the earth?

What is the weight of a 2.50-kg bag of sand on the surface of the earth?

Which one of the following statements concerning the two "gravitational constants" G, the universal gravitational constant, and g the magnitude of the acceleration due to gravity is true?

Two satellites of different masses are in the same circular orbit around the earth. Which one of the following statements is true concerning the magnitude of the gravitational force that acts on each of them?

Consider the following forces. (1) frictional (2) gravitational (3) tension (4) strong nuclear (5) normal (6) electroweak Which of the forces listed are considered fundamental forces?

Which one of the following statements best explains why the weight of an object of mass m is different on Mars than it is on the Earth?

-The book has an acceleration of 0 m/s2. Which pair of forces, excluding "action-reaction" pairs, must be equal in magnitude and opposite in direction?

An astronaut orbits the earth in a space capsule whose height above the earth is equal to the earth's radius. How does the weight of the astronaut in the capsule compare to her weight on the earth?

-Determine the magnitude of the acceleration of the spacecraft.

Two point masses m and M are separated by a distance d. If the separation d remains fixed and the masses are increased to the values 3m and 3M respectively, how does the gravitational force between them change?

A 2.00-kg projectile is fired at an angle of 20.0°. What is the magnitude of the force exerted on the projectile when it is at the highest position in its trajectory? Neglect any effects of air resistance.

-Which two forces form an "action-reaction" pair that obeys Newton's third law?

-The book has an acceleration of 0 m/s². Which pair of forces, excluding "action-reaction" pairs, must be equal in magnitude and opposite in direction?