Question 1

The fundamental force that has the shortest range is the
A) strong force.
B) weak force.
C) electromagnetic force.
D) gravitational force.

Accepted Answer

The weak force has the shortest range of all the fundamental forces, only acting over distances of around 10^-18 meters. This is because this force is mediated by the W and Z bosons, which are very massive and therefore have a very short range of interaction.

Question 2

Your friend applies a horizontal force to your 2.0-kg physics textbook, holding it stationary against a vertical wall. The static and kinetic friction coefficients between the book and the wall are 0.20 and 0.15, respectively. With what force must your friend push on the book in order for it not to slip down the wall?
A) 39 N
B) 20 N
C) 19.6 N
D) 25 N
E) 98 N

Accepted Answer

The answer of Your friend applies a horizontal force to...

Question 3

The fundamental force that binds the electrons to the nuclei to form atoms is the
A) strong force.
B) weak force.
C) electromagnetic force.
D) gravitational force.

Accepted Answer

The electromagnetic force is the fundamental force of nature that holds the electrons in orbit around the nucleus of an atom. This attraction between positively charged protons in the nucleus and negatively charged electrons maintains the stability and structure of atoms.

Question 4

The fundamental force that governs the motion of the planets is the
A) strong force.
B) weak force.
C) electromagnetic force.
D) gravitational force.

Accepted Answer

The gravitational force is the fundamental force that governs the motion of the planets. It is the force of attraction between any two objects with mass, and it is what keeps planets in orbit around the sun and moons in orbit around planets. The other choices do not apply to planetary motion, as the strong force and weak force are only important on a subatomic level, and the electromagnetic force is important for interactions between charged particles but not for planetary motion.

Question 5

An airplane flies with a constant speed at an angle of 25 degrees below the horizontal, in a straight line. Which statement below is not true?
A) The thrust is greater in magnitude than the drag.
B) The weight is greater in magnitude than the lift.
C) The net force on the plane is zero
D) The plane has constant velocity.

Accepted Answer

The answer of An airplane flies with a constant speed...

Question 6

A box is pushed across a horizontal table by a boy applying a force of 32 N to the box. A force of friction of magnitude 19 N acts opposite the direction of motion. A stiff wind also opposes the box's motion. What force does the box exert on the boy's hand?
A) 13 N
B) 32 N
C) 51 N
D) Without knowing the force the wind applies, the question cannot be answered.

Accepted Answer

According to Newton's third law, the box exerts an equal and opposite force on the boy's hand. Therefore, the force exerted by the box on the boy's hand is also 32 N.

Question 7

A box is pushed across a horizontal table at a constant speed. Of the forces acting, which pair do we know are equal in magnitude because of Newton's third law?
A) The normal force on the box and the weight of the box.
B) The normal force on the box and the normal force on the table from the box.
C) The force of kinetic friction on the box and the external pushing force applied to the box.
D) None of these are interaction pairs.

Accepted Answer

According to Newton's third law, for every action, there is an equal and opposite reaction. Therefore, the normal force on the box and the normal force on the table from the box are equal in magnitude but opposite in direction, making them an interaction pair. The weight of the box is balanced by the normal force on the box, but they are not necessarily equal in magnitude. The force of kinetic friction and the external pushing force are not an interaction pair, as they act on different objects.

Question 8

An airplane flies with a constant speed at an angle of 25 degrees above the horizontal, in a straight line. Which statement below is not true?
A) The net force on the plane is zero.
B) The lift is the same magnitude as the weight.
C) The plane has a constant velocity.
D) The thrust is greater in magnitude than the drag.

Accepted Answer

The lift must be greater than the weight to maintain the upward component of motion at an angle above the horizontal.

Question 9

A 1.75-kg picture frame is hung on the wall by means of a horizontal string on the back of the frame. The string is attached to screws on the sides if the frame, which are separated by a distance of 37.0 cm. When hung from a nail on the wall, the string is displaced at its center by a vertical distance of 4.00 cm. What is the tension T in the string?
A) 8.6 N
B) 40.6 N
C) 159 N
D) 17.2 N
E) 79.4 N

Accepted Answer

The answer of A 1.75-kg picture frame is hung on...

Question 10

A box rests on a frictionless countertop. A boy pushes horizontally to the right on the box, and a girl pushes on it to the left, yet it remains stationary. Which of the following statements is false?
A) We know the force of the boy on the box is equal in magnitude to the force of the girl on the box, because the box is in equilibrium.
B) We know the force of the boy on the box is equal in magnitude to the force of the box on the boy, because of Newton's third law.
C) We know the weight and normal force are equal in magnitude because the box is in equilibrium.
D) We know the weight and normal force are equal in magnitude because of Newton's third law.

Accepted Answer

Option D is false. Weight and normal force are not related to Newton's third law. The normal force is a reactive force that arises as a result of the contact of two surfaces, and is perpendicular to the surface. The weight is a gravitational force that pulls an object down towards the center of the Earth.

Question 11

A crate travels through a factory on a conveyor belt (without slipping) at a constant speed. The conveyer belt is inclined at some non-zero angle above the horizontal. If air resistance is negligible, what forces are active on the box?
A) normal force, weight, static friction, kinetic friction
B) normal force, weight, static friction
C) normal force, weight, static friction, force of the conveyor belt
D) normal force and weight

Accepted Answer

The forces acting on the crate are the normal force (perpendicular to the surface of the conveyor belt), the weight of the crate (due to gravity), and static friction (which prevents the crate from slipping and allows it to move along with the conveyor belt). Kinetic friction is not involved since the crate is not sliding against the belt, and the force of the conveyor belt is essentially the static friction force that moves the crate along.

Question 12

A sled has a mass of 10.0 kg. It is held in place on a frictionless 20.0 degree slope by a rope attached to a stake at the top of the slope. Find the tension in the rope, assuming it is parallel to the slope.
A) 47.9 N
B) 37.4 N
C) 94.1 N
D) 33.5 N
E) 23.8 N

Accepted Answer

The answer of A sled has a mass of 10.0...

Question 13

The fundamental force that is the weakest of the four is the
A) strong force.
B) weak force.
C) electromagnetic force.
D) gravitational force.

Accepted Answer

The gravitational force is the weakest of the four fundamental forces in nature, significantly weaker than the electromagnetic, strong, and weak forces.

Question 14

Two dogs are pulling on opposite ends of a bone, each with a force of 150 N, in opposite directions along the length of the bone. What is the tension in the bone?
A) 0 N
B) 150 N
C) 300 N
D) More information is needed to answer this question.

Accepted Answer

The tension in the bone is 150 N because the force applied by each dog is equal and opposite, resulting in a net force of 0 N on the bone itself. However, the tension within the bone is equal to the magnitude of the force applied by each dog, which is 150 N.

Question 15

A crate travels through a factory on a straight, horizontal conveyor belt at a constant speed. If air resistance is negligible, what forces are active on the box?
A) normal force, weight, static friction
B) normal force, weight, force of the conveyor belt
C) normal force, weight, force of the conveyor belt, static friction
D) normal force and weight

Accepted Answer

The crate experiences only two forces: the normal force from the conveyor belt acting upward and its weight acting downward. Since it moves at a constant speed and air resistance is negligible, there's no need to consider friction or any additional force from the conveyor belt in the vertical direction.

Question 16

A box weighing 550 N slides at constant speed across a flat parking lot, under the influence of a stiff wind. The wind applies a force of 155 N parallel to the ground. What is the angle relative to the vertical of the contact force applied by the ground?
A) 75°
B) 74°
C) 90°
D) 16°
E) 15°

Accepted Answer

The answer of A box weighing 550 N slides at...

Question 17

A worker lifts a heavy load using a two-pulley system as in the figure. If the tension in the rope segment labeled A is 1450 N, what are the weight of the load and the force that the worker exerts on the rope, respectively? 
A) 363 N, 725 N
B) 725 N, 363 N
C) 1450 N, 725 N
D) 1450 N, 1450 N
E) Insufficient information is given to answer this question.

Accepted Answer

Since the pulley system is in equilibrium, the tension in rope segment A must be the same as the tension in rope segment B. This means that the weight of the load (W) is equal to the tension in rope segment A:

W = 1450 N

The force that the worker exerts on the rope (F) is equal to half the weight of the load:

F = 0.5W = 0.5(1450 N) = 725 N

Therefore, the answer is (C) 1450 N for the weight of the load and 725 N for the force that the worker exerts on the rope.

Question 18

You find a coin resting on your physics book cover and notice that when you open the cover, the coin slips exactly when the cover reaches 25 degrees above the horizontal. What is the coefficient of static friction between the coin and book cover?
A) 2.1
B) 0.91
C) 0.37
D) 0.47
E) The question cannot be answered without knowing the coin's mass.

Accepted Answer

The angle at which the coin slips is the angle at which the gravitational component parallel to the book's surface (mg sin θ) exceeds the static friction force (μs mg cos θ). Therefore, we have:
mg sin θ = μs mg cos θ
Therefore, the coefficient of static friction is:
μs = tan θ = tan 25° = 0.47

Question 19

A 120 N traffic light is located at the midpoint of a cable between two poles. The cable makes an angle of 30° to the horizontal at each pole. What is the tension in the cable? Ignore the mass of the cable.
A) 60.0 N
B) 90.0 N
C) 140 N
D) 110 N
E) 120 N

Accepted Answer

The tension in the cable is equal to the weight of the traffic light because the system is in equilibrium, and the vertical component of the tension must balance the weight of the light. Since the angles and the situation are symmetrical, the tension is directly supporting the weight of the traffic light, which is 120 N.

Question 20

A mountain climber lies flat on the surface of a glacier (assumed frictionless), which is inclined at 30 degrees to the horizontal. He remains stationary because he is holding on to a rope that is attached to a spike in the ice further up the slope. The rope is parallel to the surface of the ice. If the force of the ice on the climber is 210 N, what is the tension in the rope?
A) 121 N
B) 105 N
C) 182 N
D) 364 N
E) 242 N

Accepted Answer

The force of the ice on the climber is perpendicular to the surface of the ice, and the tension in the rope is parallel to the surface of the ice. The two forces are perpendicular to each other, so the climber is in equilibrium. The tension in the rope is equal to the force of the ice on the climber, which is 210 N.

Quiz 4: Force and Newtons Laws of Motion

The fundamental force that has the shortest range is the

The fundamental force that binds the electrons to the nuclei to form atoms is the

The fundamental force that governs the motion of the planets is the

An airplane flies with a constant speed at an angle of 25 degrees below the horizontal, in a straight line. Which statement below is not true?

A box is pushed across a horizontal table by a boy applying a force of 32 N to the box. A force of friction of magnitude 19 N acts opposite the direction of motion. A stiff wind also opposes the box's motion. What force does the box exert on the boy's hand?

A box is pushed across a horizontal table at a constant speed. Of the forces acting, which pair do we know are equal in magnitude because of Newton's third law?

An airplane flies with a constant speed at an angle of 25 degrees above the horizontal, in a straight line. Which statement below is not true?

A box rests on a frictionless countertop. A boy pushes horizontally to the right on the box, and a girl pushes on it to the left, yet it remains stationary. Which of the following statements is false?

A crate travels through a factory on a conveyor belt (without slipping) at a constant speed. The conveyer belt is inclined at some non-zero angle above the horizontal. If air resistance is negligible, what forces are active on the box?

A sled has a mass of 10.0 kg. It is held in place on a frictionless 20.0 degree slope by a rope attached to a stake at the top of the slope. Find the tension in the rope, assuming it is parallel to the slope.

The fundamental force that is the weakest of the four is the

Two dogs are pulling on opposite ends of a bone, each with a force of 150 N, in opposite directions along the length of the bone. What is the tension in the bone?

A crate travels through a factory on a straight, horizontal conveyor belt at a constant speed. If air resistance is negligible, what forces are active on the box?

A box weighing 550 N slides at constant speed across a flat parking lot, under the influence of a stiff wind. The wind applies a force of 155 N parallel to the ground. What is the angle relative to the vertical of the contact force applied by the ground?

A worker lifts a heavy load using a two-pulley system as in the figure. If the tension in the rope segment labeled A is 1450 N, what are the weight of the load and the force that the worker exerts on the rope, respectively?

You find a coin resting on your physics book cover and notice that when you open the cover, the coin slips exactly when the cover reaches 25 degrees above the horizontal. What is the coefficient of static friction between the coin and book cover?

A 120 N traffic light is located at the midpoint of a cable between two poles. The cable makes an angle of 30° to the horizontal at each pole. What is the tension in the cable? Ignore the mass of the cable.