Question 1

A hockey puck moving at 9.0 m/s coasts to a halt in 85 m on a smooth ice surface.What is the coefficient of friction between the ice and the puck?

Accepted Answer

A)  μ = 0.219 
B)  μ = 0.049 
C)  μ = 0.097 
D)  μ = 0.146 
E)  ​μ = 0.243 
A)  μ = 0.219 
B)  μ = 0.049 
C)  μ = 0.097 
D)  μ = 0.146 
E)  ​μ = 0.243

Question 2

The acceleration due to gravity on the Moon's surface is one-sixth that on Earth.An astronaut's life support backpack weighs 350 lb on Earth.What does it weigh on the Moon?

Accepted Answer

A)  2,100 lb 
B)  350 lb 
C)  356 lb 
D)  58 lb 
E)  ​344 lb 
A)  2,100 lb 
B)  350 lb 
C)  356 lb 
D)  58 lb 
E)  ​344 lb

Question 3

Two ropes are attached to a 35-kg object.The first rope applies a force of 20 N and the second,55 N.If the two ropes are perpendicular to each other,what is the resultant acceleration of the object?

Accepted Answer

A)  1.7 m/s2 
B)  20 m/s2 
C)  2.1 m/s2 
D)  59 m/s2 
E)  0.6 ​m/s2 
A)  1.7 m/s2 
B)  20 m/s2 
C)  2.1 m/s2 
D)  59 m/s2 
E)  0.6 ​m/s2

Question 4

Three identical 6.0-kg cubes are placed on a horizontal frictionless surface in contact with one another.The cubes are lined up from left to right and a 36-N force is applied to the left side of the left cube causing all three cubes to accelerate to the right.If the cubes are each subject to a frictional force of 6.0 N,what is the magnitude of the force exerted on the middle cube by the left cube in this case?

Accepted Answer

A)  12 N 
B)  24 N 
C)  6.0 N 
D)  ​36 N 
E)  ​none of the above 
A)  12 N 
B)  24 N 
C)  6.0 N 
D)  ​36 N 
E)  ​none of the above

Question 5

An automobile of mass 3,000 kg moving at 45 m/s is braked suddenly with a constant braking force of 9,000 N.How far does the car travel before stopping?

Accepted Answer

A)  8 m 
B)  338 m 
C)  169 m 
D)  507 m 
E)  ​18 m 
A)  8 m 
B)  338 m 
C)  169 m 
D)  507 m 
E)  ​18 m

Question 6

A 12-kg mass is placed on a 29° incline and friction keeps it from sliding.The coefficient of static friction in this case is 0.633,and the coefficient of sliding friction is 0.524.The mass is given a shove causing it to slide down the incline.What is the frictional force while the mass is sliding?

Accepted Answer

A)  57.01 N 
B)  102.86 N 
C)  53.90 N 
D)  65.11 N 
E)  ​10.50 N 
A)  57.01 N 
B)  102.86 N 
C)  53.90 N 
D)  65.11 N 
E)  ​10.50 N

Question 7

There are five books in a stack,each with a weight of 8N.The coefficient of friction between all the books is 0.4 as is the coefficient between the table and the bottom book.What horizontal push must I just exceed on the next to bottom book to start sliding the top four books off the bottom one?

Accepted Answer

A)  3.2 N 
B)  12.8 N 
C)  1.6 N 
D)  16 N 
E)  ​32 N 
A)  3.2 N 
B)  12.8 N 
C)  1.6 N 
D)  16 N 
E)  ​32 N

Question 8

A block is launched up an incline plane.After going up the plane,it slides back down to its starting position.The coefficient of friction between the block and the plane is 0.3.The time for the trip up the plane:

Accepted Answer

A)  is the same as the time for the trip down. 
B)  is more than the time for the trip down. 
C)  is less than the time for the trip down. 
D)  cannot be found without knowing the angle of inclination. 
A)  is the same as the time for the trip down. 
B)  is more than the time for the trip down. 
C)  is less than the time for the trip down. 
D)  cannot be found without knowing the angle of inclination.

Question 9

If we know an object is moving at constant velocity,we may assume:

Accepted Answer

A)  the net force acting on the object is zero. 
B)  there are no forces acting on the object. 
C)  the object is accelerating. 
D)  the object is losing mass. 
A)  the net force acting on the object is zero. 
B)  there are no forces acting on the object. 
C)  the object is accelerating. 
D)  the object is losing mass.

Question 10

A 5,500-N weight is held suspended in equilibrium by two cables.Cable 1 applies a horizontal force to the right of the object and has a tension,T1.Cable 2 applies a force upward and to the left at an angle of 35.0° to the negative x-axis and has a tension,T2.What is the tension,T1?

Accepted Answer

A)  3,850 N 
B)  7,860 N 
C)  4,510 N 
D)  9,590 N 
E)  ​11,710 N 
A)  3,850 N 
B)  7,860 N 
C)  4,510 N 
D)  9,590 N 
E)  ​11,710 N

Question 11

Two blocks are at rest on a horizontal frictionless surface with a compressed spring between them.The 5.0-kg block accelerates when the string holding the system in compression is cut and the 10-kg box accelerates in the opposite direction.What is the magnitude of the force from the expanding spring on the 10-kg box when the 5.0-kg box is undergoing an acceleration of 9.0 m/s2?

Accepted Answer

A)  22.5 N 
B)  90 N 
C)  135 N 
D)  45 N 
E)  ​0 N 
A)  22.5 N 
B)  90 N 
C)  135 N 
D)  45 N 
E)  ​0 N

Question 12

The coefficient of static friction between the tires of a car and the street is μs = 0.67.Of the following,what is the steepest inclination angle of a street on which a car can be parked (with wheels locked)without slipping?

Accepted Answer

A)  29° 
B)  39° 
C)  34° 
D)  44° 
E)  ​31° 
A)  29° 
B)  39° 
C)  34° 
D)  44° 
E)  ​31°

Question 13

A karate master strikes a board with an initial velocity of 18.0 m/s,decreasing to 4.0 m/s as his hand passes through the board.If the time of contact with the board is 0.002 s,and the mass of the coordinated hand and arm is 1.0 kg,what is the force exerted on the board?

Accepted Answer

A)  11,000 N 
B)  0.028 N 
C)  0.044 N 
D)  ​7,000 N 
E)  ​9,000 N 
A)  11,000 N 
B)  0.028 N 
C)  0.044 N 
D)  ​7,000 N 
E)  ​9,000 N

Question 14

A 479-N crate rests on an ramp;the maximum angle just before it slips is 20° with the horizontal.What is the coefficient of static friction between crate and ramp surfaces?

Accepted Answer

A)  2.75 
B)  0.58 
C)  1.73 
D)  0.36 
E)  ​0.72 
A)  2.75 
B)  0.58 
C)  1.73 
D)  0.36 
E)  ​0.72

Question 15

A boxcar of mass 300 tons at rest becomes uncoupled on a 2.0° grade.If the track is considered to be frictionless,what speed does the boxcar have after 8 seconds?

Accepted Answer

A)  8.5 m/s 
B)  0 m/s 
C)  35.1 m/s 
D)  2.7 m/s 
E)  ​0.3 m/s 
A)  8.5 m/s 
B)  0 m/s 
C)  35.1 m/s 
D)  2.7 m/s 
E)  ​0.3 m/s

Question 16

As I slide a box at constant speed up a frictionless slope,pulling parallel to the slope,the tension in the rope will be:

Accepted Answer

A)  greater than the tension would be if the box were stationary. 
B)  greater than the weight of the box. 
C)  equal to the weight of the box. 
D)  less than the weight of the box. 
A)  greater than the tension would be if the box were stationary. 
B)  greater than the weight of the box. 
C)  equal to the weight of the box. 
D)  less than the weight of the box.

Question 17

A 25-kg traffic light hangs midway on a cable between two poles 50 meters apart.If the sag in the cable is 0.40 meters,what is the tension in each side of the cable?

Accepted Answer

A)  120 N 
B)  15,310 N 
C)  ​7,660 N 
D)  ​780 N 
E)  ​30,630 N 
A)  120 N 
B)  15,310 N 
C)  ​7,660 N 
D)  ​780 N 
E)  ​30,630 N

Question 18

Which of the following is an example of the type of force that acts at a distance?

Accepted Answer

A)  gravitational 
B)  magnetic 
C)  electrical 
D)  all of the above 
A)  gravitational 
B)  magnetic 
C)  electrical 
D)  all of the above

Question 19

Two forces act on a 5.00-kg object.One of the forces is 11.0 N.If the object accelerates at 4.00 m/s2,what is the greatest possible magnitude of the other force?

Accepted Answer

A)  1.0 N 
B)  9.0 N 
C)  31.0 N 
D)  16.7 N 
E)  ​51.0 N 
A)  1.0 N 
B)  9.0 N 
C)  31.0 N 
D)  16.7 N 
E)  ​51.0 N

Question 20

A horizontal force of 750 N is needed to overcome the force of static friction between a level floor and a 350-kg crate.What is the acceleration of the crate if the 750-N force is maintained after the crate begins to move and the coefficient of kinetic friction is 0.13?

Accepted Answer

A)  0.9 m/s2 
B)  3.4 m/s2 
C)  2.7 m/s2 
D)  1.3 m/s2 
E)  ​1.9 m/s2 
A)  0.9 m/s2 
B)  3.4 m/s2 
C)  2.7 m/s2 
D)  1.3 m/s2 
E)  ​1.9 m/s2

Exam 4: The Laws of Motion

A hockey puck moving at 9.0 m/s coasts to a halt in 85 m on a smooth ice surface.What is the coefficient of friction between the ice and the puck?

The acceleration due to gravity on the Moon's surface is one-sixth that on Earth.An astronaut's life support backpack weighs 350 lb on Earth.What does it weigh on the Moon?

Two ropes are attached to a 35-kg object.The first rope applies a force of 20 N and the second,55 N.If the two ropes are perpendicular to each other,what is the resultant acceleration of the object?

An automobile of mass 3,000 kg moving at 45 m/s is braked suddenly with a constant braking force of 9,000 N.How far does the car travel before stopping?

There are five books in a stack,each with a weight of 8N.The coefficient of friction between all the books is 0.4 as is the coefficient between the table and the bottom book.What horizontal push must I just exceed on the next to bottom book to start sliding the top four books off the bottom one?

A block is launched up an incline plane.After going up the plane,it slides back down to its starting position.The coefficient of friction between the block and the plane is 0.3.The time for the trip up the plane:

If we know an object is moving at constant velocity,we may assume:

A 5,500-N weight is held suspended in equilibrium by two cables.Cable 1 applies a horizontal force to the right of the object and has a tension,T1.Cable 2 applies a force upward and to the left at an angle of 35.0° to the negative x-axis and has a tension,T2.What is the tension,T1?

The coefficient of static friction between the tires of a car and the street is μs = 0.67.Of the following,what is the steepest inclination angle of a street on which a car can be parked (with wheels locked)without slipping?

A karate master strikes a board with an initial velocity of 18.0 m/s,decreasing to 4.0 m/s as his hand passes through the board.If the time of contact with the board is 0.002 s,and the mass of the coordinated hand and arm is 1.0 kg,what is the force exerted on the board?

A 479-N crate rests on an ramp;the maximum angle just before it slips is 20° with the horizontal.What is the coefficient of static friction between crate and ramp surfaces?

A boxcar of mass 300 tons at rest becomes uncoupled on a 2.0° grade.If the track is considered to be frictionless,what speed does the boxcar have after 8 seconds?

As I slide a box at constant speed up a frictionless slope,pulling parallel to the slope,the tension in the rope will be:

A 25-kg traffic light hangs midway on a cable between two poles 50 meters apart.If the sag in the cable is 0.40 meters,what is the tension in each side of the cable?

Which of the following is an example of the type of force that acts at a distance?

Two forces act on a 5.00-kg object.One of the forces is 11.0 N.If the object accelerates at 4.00 m/s2,what is the greatest possible magnitude of the other force?

A horizontal force of 750 N is needed to overcome the force of static friction between a level floor and a 350-kg crate.What is the acceleration of the crate if the 750-N force is maintained after the crate begins to move and the coefficient of kinetic friction is 0.13?

Introduction

Introduction: Part A

Motion in One Dimension

Motion in One Dimension: Part A

Vectors and Two-Dimensional Motion

Vectors and Two-Dimensional Motion: Part A

The Laws of Motion: Part A

Energy

Energy: Part A

Momentum and Collisions

Momentum and Collisions: Part A

Rotational Motion and the Law of Gravity

Rotational Motion and the Law of Gravity: Part A

Rotational Equilibrium and Rotational Dynamics

Rotational Equilibrium and Rotational Dynamics: Part A

Solids and Fluids

Solids and Fluids: Part A

Thermal Physics

Thermal Physics: Part A

Energy in Thermal Processes Heat and Internal Energy

Energy in Thermal Processes Heat and Internal Energy: Part A

The Laws of Thermodynamics Work in Thermodynamic Processes

The Laws of Thermodynamics Work in Thermodynamic Processes: Part A

Vibrations and Waves

Vibrations and Waves: Part A

Sound

Sound: Part A

Electric Forces and Electric Fields

Electric Forces and Electric Fields: Part A

Electrical Energy and Capacitance

Electrical Energy and Capacitance: Part A

Current and Resistance Electric Current

Current and Resistance Electric Current: Part A

Direct-Current Circuits Sources of EMF

Direct-Current Circuits Sources of EMF: Part A

Magnetism Magnets

Magnetism Magnets: Part A

Induced Voltages and Inductance

Induced Voltages and Inductance: Part A

Alternating-Current Circuits and Electromagnetic Waves

Alternating-Current Circuits and Electromagnetic Waves: Part A

Reflection and Refraction of Light

Reflection and Refraction of Light: Part A

Mirrors and Lenses

Mirrors and Lenses: Part A

Wave Optics

Wave Optics: Part A

Optical Instruments

Optical Instruments: Part A

Relativity

Relativity: Part A

Quantum Physics Blackbody Radiation and Plancks Hypothesis

Quantum Physics Blackbody Radiation and Plancks Hypothesis: Part A

Atomic Physics

Atomic Physics: Part A

Nuclear Physics

Nuclear Physics: Part A

Nuclear Energy and Elementary Particles

Nuclear Energy and Elementary Particles: Part A

Particle Collisions, Mediating Photons, and Quark Structures: Exploring the Fundamentals of Physics

Filters

A 5,500-N weight is held suspended in equilibrium by two cables.Cable 1 applies a horizontal force to the right of the object and has a tension,T₁.Cable 2 applies a force upward and to the left at an angle of 35.0° to the negative x-axis and has a tension,T₂.What is the tension,T₁?

The coefficient of static friction between the tires of a car and the street is μ_s = 0.67.Of the following,what is the steepest inclination angle of a street on which a car can be parked (with wheels locked)without slipping?

Two forces act on a 5.00-kg object.One of the forces is 11.0 N.If the object accelerates at 4.00 m/s²,what is the greatest possible magnitude of the other force?