Question 1

A freight train consists of an engine and several identical cars on a straight, level track. Which of the following statements is true?

Accepted Answer

A)  If the train is moving at constant speed, the engine must be pulling with a force greater than the train's weight. 
B)  If the train is moving at constant speed, the engine's pull on the first car must exceed that car's backward pull on the engine. 
C)  If the train is coasting, its inertia makes it slow down and eventually stop. 
D)  If the train is moving at constant speed, the engine's pull must be equal to the force of friction. 
A)  If the train is moving at constant speed, the engine must be pulling with a force greater than the train's weight. 
B)  If the train is moving at constant speed, the engine's pull on the first car must exceed that car's backward pull on the engine. 
C)  If the train is coasting, its inertia makes it slow down and eventually stop. 
D)  If the train is moving at constant speed, the engine's pull must be equal to the force of friction. D

Question 2

A mass sits at rest on top of a table. Which two forces are interaction pair forces and thus are equal and opposite?

Accepted Answer

A)  the force of gravity on the mass due to the Earth and the force of gravity on the Earth due to the mass 
B)  the force of gravity on the mass due to the Earth and the contact force on the table due to the mass 
C)  the contact force on the mass due to the table and the force of gravity on the Earth due to the mass 
D)  the force of gravity on the mass due to the Earth and the contact force on the mass due to the table 
A)  the force of gravity on the mass due to the Earth and the force of gravity on the Earth due to the mass 
B)  the force of gravity on the mass due to the Earth and the contact force on the table due to the mass 
C)  the contact force on the mass due to the table and the force of gravity on the Earth due to the mass 
D)  the force of gravity on the mass due to the Earth and the contact force on the mass due to the table A

Question 3

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?

Accepted Answer

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. 
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. D

Question 4

An object of mass m is hanging by a string from the roof of an elevator. The elevator is moving downward and slowing down. What is the tension in the string?

Accepted Answer

A)  greater than mg 
B)  less than mg 
C)  equal to mg 
D)  depends on the speed of the elevator 
A)  greater than mg 
B)  less than mg 
C)  equal to mg 
D)  depends on the speed of the elevator

Question 5

A 90.0 N crate of apples sits at rest on a ramp that runs from the ground to the bed of a truck. The ramp is inclined at 20° to the horizontal. What is the normal force exerted on the crate by the ramp?

Accepted Answer

A)  86.9 N 
B)  84.6 N 
C)  75.8 N 
D)  30.8 N 
E)  38.5 N 
A)  86.9 N 
B)  84.6 N 
C)  75.8 N 
D)  30.8 N 
E)  38.5 N

Question 6

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?

Accepted Answer

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 
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

Question 7

A rope is connected to a spring scale on the left and exerts a force T1. Another rope is connected to the scale on the right and exerts a force T2. The scale shows a reading of Ts = 120 N. The values of T1 and T2 are

Accepted Answer

A)  T1 = 80 N, and T2 = 80 N. 
B)  T1 = 120 N, and T2 = 120 N. 
C)  T1 = 240 N, and T2 = 240 N. 
D)  T1 = 80 N, and T2 = 120 N. 
A)  T1 = 80 N, and T2 = 80 N. 
B)  T1 = 120 N, and T2 = 120 N. 
C)  T1 = 240 N, and T2 = 240 N. 
D)  T1 = 80 N, and T2 = 120 N.

Question 8

Two masses are being pulled up a 30.0 degree incline by a force F parallel to the incline. The acceleration down the incline is 1.00 m/s2 and the velocity is up the incline. The force is applied to a 200 kg mass and a string connects the 200 kg mass to a 150 kg mass. There is no friction. The tension in the string is

Accepted Answer

A)  585 N. 
B)  1470 N. 
C)  980 N. 
D)  771 N. 
E)  1365 N. 
A)  585 N. 
B)  1470 N. 
C)  980 N. 
D)  771 N. 
E)  1365 N.

Question 9

The diagram below represents an ideal pulley system (no mass or friction). What is the force required to lift the 45 kg mass?

Accepted Answer

A)  442 N 
B)  393 N 
C)  221 N 
D)  147 N 
A)  442 N 
B)  393 N 
C)  221 N 
D)  147 N

Question 10

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?

Accepted Answer

A)  0 N 
B)  150 N 
C)  300 N 
D)  More information is needed to answer this question. 
A)  0 N 
B)  150 N 
C)  300 N 
D)  More information is needed to answer this question.

Question 11

The force that holds charged atoms together is the

Accepted Answer

A)  gravitational force. 
B)  electromagnetic force. 
C)  weak interaction. 
D)  strong nuclear force. 
A)  gravitational force. 
B)  electromagnetic force. 
C)  weak interaction. 
D)  strong nuclear force.

Question 12

A tractor of mass M1 = 2,000 kg is pulling a trailer of mass M2 = 5,000 kg. If the tractor-trailer is accelerated at 2.0 m/s2, and air resistance is negligible, then the tension in the trailer hitch that connects the trailer to the tractor is

Accepted Answer

A)  6,000 N. 
B)  8,000 N. 
C)  9,000 N. 
D)  10,000 N. 
E)  11,000 N. 
A)  6,000 N. 
B)  8,000 N. 
C)  9,000 N. 
D)  10,000 N. 
E)  11,000 N.

Question 13

A block is at rest on a wooden ramp. The coefficient of static friction between the block and ramp is 0.35. If the ramp is gradually elevated on one side, at what angle (between the ramp and the horizontal) will the block first begin to slide?

Accepted Answer

A)  17° 
B)  19° 
C)  29° 
D)  20° 
E)  22° 
A)  17° 
B)  19° 
C)  29° 
D)  20° 
E)  22°

Question 14

The fundamental force that is the principal cause of what we experience as friction is the

Accepted Answer

A)  gravitational force. 
B)  electromagnetic force. 
C)  weak force. 
D)  strong force. 
A)  gravitational force. 
B)  electromagnetic force. 
C)  weak force. 
D)  strong force.

Question 15

Three objects experience interactions. Object A has mass, object B has electrical charge, and object C has both mass and electrical charge. Which of the following statements is true?

Accepted Answer

A)  Object A and object B experience an electrical interaction. 
B)  Object A and object C experience a gravitational interaction. 
C)  Object A and object C experience an electrical interaction. 
D)  Object A and object B experience a gravitational interaction. 
A)  Object A and object B experience an electrical interaction. 
B)  Object A and object C experience a gravitational interaction. 
C)  Object A and object C experience an electrical interaction. 
D)  Object A and object B experience a gravitational interaction.

Question 16

Two masses are being pulled up a frictionless 30.0 degree incline by a force F parallel to the incline. The acceleration up the incline is 1.00 m/s2. The force is applied to a 200 kg mass and a string connects the 200 kg mass to a 150 kg mass. The force F is

Accepted Answer

A)  875 N. 
B)  980 N. 
C)  1,140 N. 
D)  1,720 N. 
E)  2,070 N. 
A)  875 N. 
B)  980 N. 
C)  1,140 N. 
D)  1,720 N. 
E)  2,070 N.

Question 17

A person weighs 155 pounds. What is the person's weight in newtons?

Accepted Answer

A)  155 N 
B)  689 N 
C)  39.3 N 
D)  392 N 
A)  155 N 
B)  689 N 
C)  39.3 N 
D)  392 N

Question 18

What is the gravitational field strength on the surface of the Earth? (G = 6.67 × 10-11 N m2/kg2, the mass of the Earth is 5.98 × 1024 kg, and the radius of the Earth is 6.38 × 106 m.)

Accepted Answer

A)  3.40 N/kg. 
B)  6.20 N/kg. 
C)  9.80 N/kg. 
D)  10.1 N/kg. 
E)  20.3 N/kg. 
A)  3.40 N/kg. 
B)  6.20 N/kg. 
C)  9.80 N/kg. 
D)  10.1 N/kg. 
E)  20.3 N/kg.

Question 19

You are standing on a bathroom scale in an elevator that is not moving, and the scale reads 500 N. If the elevator were instead moving downward at a constant velocity of 4.50 m/s, what would the scale read?

Accepted Answer

A)  100 N 
B)  450 N 
C)  500 N 
D)  750 N 
E)  250 N 
A)  100 N 
B)  450 N 
C)  500 N 
D)  750 N 
E)  250 N

Question 20

A 78.0 kg object is travelling due north at 15.2 m/s when it begins to experience a constant net force of 1.72 kN toward the south. How long will it take to stop under the influence of this force?

Accepted Answer

A)  1.45 s 
B)  2.98 s 
C)  0.335 s 
D)  0.689 s 
A)  1.45 s 
B)  2.98 s 
C)  0.335 s 
D)  0.689 s

Exam 4: Force and Newtons Laws of Motion

A freight train consists of an engine and several identical cars on a straight, level track. Which of the following statements is true?

A mass sits at rest on top of a table. Which two forces are interaction pair forces and thus are equal and opposite?

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?

An object of mass m is hanging by a string from the roof of an elevator. The elevator is moving downward and slowing down. What is the tension in the string?

A 90.0 N crate of apples sits at rest on a ramp that runs from the ground to the bed of a truck. The ramp is inclined at 20° to the horizontal. What is the normal force exerted on the crate by the ramp?

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 rope is connected to a spring scale on the left and exerts a force T1. Another rope is connected to the scale on the right and exerts a force T2. The scale shows a reading of Ts = 120 N. The values of T1 and T2 are

The diagram below represents an ideal pulley system (no mass or friction). What is the force required to lift the 45 kg mass?

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?

The force that holds charged atoms together is the

A tractor of mass M1 = 2,000 kg is pulling a trailer of mass M2 = 5,000 kg. If the tractor-trailer is accelerated at 2.0 m/s2, and air resistance is negligible, then the tension in the trailer hitch that connects the trailer to the tractor is

A block is at rest on a wooden ramp. The coefficient of static friction between the block and ramp is 0.35. If the ramp is gradually elevated on one side, at what angle (between the ramp and the horizontal) will the block first begin to slide?

The fundamental force that is the principal cause of what we experience as friction is the

Three objects experience interactions. Object A has mass, object B has electrical charge, and object C has both mass and electrical charge. Which of the following statements is true?

Two masses are being pulled up a frictionless 30.0 degree incline by a force F parallel to the incline. The acceleration up the incline is 1.00 m/s2. The force is applied to a 200 kg mass and a string connects the 200 kg mass to a 150 kg mass. The force F is

A person weighs 155 pounds. What is the person's weight in newtons?

What is the gravitational field strength on the surface of the Earth? (G = 6.67 × 10-11 N m2/kg2, the mass of the Earth is 5.98 × 1024 kg, and the radius of the Earth is 6.38 × 106 m.)

You are standing on a bathroom scale in an elevator that is not moving, and the scale reads 500 N. If the elevator were instead moving downward at a constant velocity of 4.50 m/s, what would the scale read?

A 78.0 kg object is travelling due north at 15.2 m/s when it begins to experience a constant net force of 1.72 kN toward the south. How long will it take to stop under the influence of this force?

Introduction

Motion Along a Line

Motion in a Plane

Circular Motion

Conservation of Energy

Linear Momentum

Torque and Angular Momentum

Fluids

Elasticity and Oscillations

Waves

Sound

Temperature and the Ideal Gas

Heat

Thermodynamics

Electric Forces and Fields

Electric Potential

Electric Current and Circuits

Magnetic Forces and Fields

Electromagnetic Induction

Alternating Current

Electromagnetic Waves

Reflection and Refraction of Light

Optical Instruments

Interference and Diffraction

Relativity

Early Quantum Physics and the Photon

Quantum Physics

Nuclear Physics

Particle Physics

Filters

A rope is connected to a spring scale on the left and exerts a force T₁. Another rope is connected to the scale on the right and exerts a force T_2. The scale shows a reading of T_s= 120 N. The values of T₁ and T₂ are

A tractor of mass M₁ = 2,000 kg is pulling a trailer of mass M₂ = 5,000 kg. If the tractor-trailer is accelerated at 2.0 m/s², and air resistance is negligible, then the tension in the trailer hitch that connects the trailer to the tractor is

Two masses are being pulled up a frictionless 30.0 degree incline by a force F parallel to the incline. The acceleration up the incline is 1.00 m/s². The force is applied to a 200 kg mass and a string connects the 200 kg mass to a 150 kg mass. The force F is

What is the gravitational field strength on the surface of the Earth? (G = 6.67 × 10^-11 N m²/kg², the mass of the Earth is 5.98 × 10²⁴ kg, and the radius of the Earth is 6.38 × 10⁶ m.)