Expert TA Problems are good problems to have.
You know it, and we know it. Students don’t learn physics by only listening to instructors describe the material. To close the loop and master the concepts presented in class, they need to practice by solving problems and applying the principles and methods taught in class.
Every aspect of Expert TA’s online homework and tutorial system supports the goal of helping students master physics by solving problems themselves.
Because problem solving is so crucial, Expert TA has created an Independent Library of problems unlike any other in the industry.
In·de·pend·ent (in’dipen’dənt). adj. 1. Free from the influence or control of others. a) free from the rule of another; b) free from persuasion or bias; selfdetermined; selfreliant, etc.
The “Story” Behind the Library
The story of Expert TA’s Independent Library is the story of unintended consequences.
When we started out, we assumed that we would team up with publishers to build a problem library. Then, as we worked with authors and leading physics educators to develop some problems to test the advanced algorithms that are the backbone of Expert TA, we came to understand the evergrowing need for textbook independent solutions.
We share instructors’ and students’ concerns about the seemingly endless increase in costs of the “bundles” from publishers. We see the impact of the lack of fresh new problems as well as the unproductive consequences of the availability of problem solutions on the internet.
So we listened. We’ve made excellent educational tools affordable. We hired amazing contributors to help build our problem library. Our authors have outstanding credentials and real experience. This cadre of experts helps us add fresh, new problem content, expanding our Library regularly. We have a process to keep the solutions to our problems off the internet.
And, our detailed analytics point us to areas that need additional problems or more feedback modules so we can constantly improve our content to meet instructors’ and students’ needs.
Key Benefits of our Library
 Multistep problems authored and individually vetted by physics experts
 Each problem independently peerreviewed
 Largest collection of symbolic problems available on the market
 Five levels of difficulty to match your course
 Algebrabased, calculusbased, and conceptualbased problems
 Varied complexity, including quick, onetotwo part questions, multistep questions, and more involved problems that capture more of the students’ work
 Randomized numbers and phrases for the majority of our problems
 Our everexpanding library includes problem sets from OpenStax College’s free online College Physics text.
 Collect analytics to add problems and feedback to address common incorrect answers
Providing wellwritten and expertly vetted physics problems is the core of what we do at Expert TA.
Each of our deeply experienced team of more than 30 problem authors brings a unique perspective.
Our problems are written for today’s students by PhDs who understand firsthand how the right touch of hints and feedback at just the right time can help develop students’ problem solving skills.
If you are an educator who cares about student learning and are interested in contributing to our problem library as a problem author, reviewer, or in any other way, we want to hear from you. Please check our Careers page to review current openings for contributors. Or, send us an email with your resume so we can get to know each other better.
Viewing our Library
Our Library is easy to use and navigate. Problems are displayed similarly to the way they appear at the end of the chapter of a book. It’s easy to preview problems and to select the perfect ones for your assignment. There’s no digging through multiple screens. Everything you need is front and center.
In addition to making problems easy to view, we also allow you to filter problems by difficulty level and type to find exactly what you’re looking for.
Problem Difficulty
Our expert team of authors ranks problems from 1 to 5 in terms of difficulty within their category. Category is defined by the problem type (conceptual, algebra or calculus) and the Expert TA section. The ranking is a rough estimate based on how much skill and how much time it will take a student to complete a problem.
Here are the general definitions of difficulty levels in Expert TA.
 Level 1 problems are based on the most simple thing that can be reasonably asked. Usually no algebraic manipulations or unit conversions are required.
Level 1 Problem Example
 Level 2 problems are still easy, but slightly more difficult than Level 1. There may be some manipulations or unit conversions with one or two easier parts involved.
Level 2 Problem Example
 Level 3 problems require basic problem solving and mathematical skill. They test a common physical concept. Typically there are two to four easier parts involved.
Level 3 Problem Example
 Level 4 problems are harder. They typically require skills that students may not have or involve a more difficult physical concept. These range from three to six parts.
Level 4 Problem Example
 Level 5 problems are the most difficult problems in the system. They will typically be testing a difficult physical concept, require problem solving skills which many students may not have, or be quite long with more than five parts.
Level 5 Problem Example
Problem Type
The problem type filter can be used to choose problems based the type of calculations, if any, required. There are three possible types:
 Conceptual (CP): These problems typically do not involve any calculations, except those which are extremely trivial. An example might be “if the distance doubles, what happens to the force?”
Conceptual Problem Example
 Algebra (Alg): These are problems appropriate for algebrabased classes. No calculus ability is required.
Algebra Problem Example
 Calculus (Calc): These problems are appropriate for calculusbased classes. This does not mean that the problem will always involve calculus, but it may include parts that are not appropriate for an algebrabased class.
Calculus Problem Example
Table of Contents
Here is the Table of Contents for our Independent Library, including chapter and section names. To preview problems more in depth, contact us to set up a demonstration and trial access.
Units and Physical Quantities 
1.1 – Fundamental Elements 
1.2 – Density 
1.3 – Dimensional Analysis 
1.4 – Unit Conversions 
1.5 – Significant Figures 

Vectors 
2.2 – Vector and Scalar Quantities 
2.3 – Vector Properties 
2.4 – Vector Components and Unit Vectors 

1D Motion 
3.1 – Displacement, Velocity and Speed 
3.3 – Acceleration 
3.4 – Motion Diagrams 
3.5 – OneDimensional Motion with Constant Acceleration 
3.6 – Objects in Free Fall 

2D Motion 
4.1 – Displacement, Velocity and Acceleration Vectors 
4.2 – TwoDimensional Motion and Constant Acceleration 
4.3 – Projectile Motion 
4.4 – Uniform Circular Motion 
4.5 – Tangential and Radial Acceleration 
4.6 – Relative Motion 

Newton’s Laws 
5.1 – Newton’s First Law and Inertial Frames 
5.3 – Newton’s Second Law 
5.4 – Gravity and Weight 
5.5 – Newton’s Third Law 
5.6 – Frictional Forces 
5.7 – Application of Newton’s Laws 

Circular Motion 
6.1 – Newton’s Second Law Applied to Uniform Circular Motion 

Work and Kinetic Energy 
7.1 – Work Done by a Constant Force 
7.2 – The Scalar Product of Two Vectors 
7.3 – Work Done by a Varying Force 
7.4 – Kinetic Energy and the WorkKinetic Energy Theorem 
7.5 – Power 

Potential Energy and Mechanical Energy 
8.1 – Potential Energy 
8.2 – Conservative and Nonconservative Forces 
8.3 – Conservative Forces and Potential Energy 
8.4 – Conservation of Energy 
8.5 – Work Done by Nonconservative Forces 
8.6 – The Principal of WorkEnergy 

Momentum, Impulse and Collisions 
9.1 – Conservation of Linear Momentum 
9.2 – Impulse and Momentum 
9.3 – Collisions 
9.4 – Elastic and Inelastic Collisions in One Dimension 
9.5 – TwoDimensional Collisions 
9.6 – The Center of Mass 

Rotation of a Rigid Object 
10.1 – Angular Displacement, Velocity and Acceleration 
10.2 – Rotational Kinematics 
10.3 – Angular and Linear Quantities 
10.4 – Rotational Energy 
10.5 – Calculation of Moments of Inertia 
10.6 – Torque (scalar analysis) 
10.7 – Torque and Angular Acceleration 
10.8 – Work, Power and Energy in Rotational Motion 

Rotational Motion Dynamics 
11.1 – Rolling Motion of a Rigid Object 
11.2 – Torque (Crossproducts) 
11.3 – Angular Momentum of a Particle 
11.4 – Angular Momentum of a Rotating Rigid Object 
11.5 – Conservation of Angular Momentum 

Equilibrium and Elasticity 
12.1 – The Conditions for Equilibrium 
12.3 – Rigid Objects in Static Equilibrium 
12.4 – Elastic Properties of Solids 

Periodic Motion 
13.1 – Simple Harmonic Motion 
13.2 – The Block/Spring System Revisited 
13.3 – Energy of the Simple Harmonic Oscillator 
13.4 – The Pendulum 
13.5 – Comparing Simple Harmonic Motion with Uniform Circular Motion 

Gravitation 
14.1 – Newton’s Law of Universal Gravitation 
14.2 – Measuring the Gravitational Constant 
14.3 – FreeFall Acceleration and the Gravitational Force 
14.4 – Kepler’s Laws 
14.5 – The Law of Gravity and the Motion of Planets 
14.6 – The Gravitational Field 
14.7 – Gravitational Potential Energy 
14.8 – Energy Considerations in Planetary and Satellite Motion 

Fluid Mechanics 
15.1 – Pressure 
15.2 – Variation of Pressure with Depth 
15.3 – Pressure Measurements 
15.4 – Buoyant Forces and Archimedes’s Principle 
15.5 – Fluid Dynamics 
15.6 – Streamlines and the Equation of Continuity 
15.7 – Bernoulli’s Equation 

Mechanical Waves 
16.1 – Basic Variables of Wave Motion 
16.3 – OneDimensional Traveling Waves 
16.4 – Superposition and Interference 
16.5 – The Speed of Waves on Strings 

Sound Waves 
17.1 – Speed of Sound Waves 
17.2 – Periodic Sound Waves 
17.3 – Intensity of Periodic Sound Waves 
17.5 – The Doppler Effect 

Superposition and Standing Waves 
18.1 – Superposition and Interference of Sinusoidal Waves 
18.2 – Standing Waves 
18.3 – Resonance 
18.4 – Standing Waves in Air Columns 
18.5 – Beats: Interference in Time 

Temperature 
19.2 – Thermometers and Temperature Scales 
19.3 – The ConstantVolume Gas Thermometer and the Kelvin Scale 
19.4 – Thermal Expansion of Solids and Liquids 
19.5 – Macroscopic Description of an Ideal Gas 

Heat and the First Law of Thermodynamics 
20.1 – Heat and Internal Energy 
20.2 – Heat Capacity and Specific Heat 
20.3 – Latent Heat 
20.4 – Work and Heat in Thermodynamic Processes 
20.5 – The First Law of Thermodynamics 
20.6 – Some Applications of the First Law of Thermodynamics 
20.7 – Energy Transfer Mechanisms 

The Second Law of Thermodynamics and Applications 
21.1 – Heat Engines and the Second Law of Thermodynamics 
21.2 – Reversible and Irreversible Processes 
21.3 – The Carnot Engine 
21.5 – The Gasoline Engine 
21.6 – Heat Pumps and Refrigerators 
21.7 – Entropy 
21.8 – Entropy Changes in Irreversible Processes 

Electric Charge and Electric Fields 
22.1 – Properties of Electric Charges 
22.2 – Insulators and Conductors 
22.3 – Coulomb’s Law 
22.4 – The Electric Field 
22.5 – Electric Field of a Continuous Charge Distribution 
22.6 – Electric Field Lines 
22.7 – Motion of Charged Particles in a Uniform Electric Field 
22.8 – Electric Field Calculations 

Gauss’s Law 
23.1 – Electric Flux 
23.2 – Gauss’s Law 
23.3 – Application of Gauss’s Law 
23.4 – Conductors in Electrostatic Equilibrium 

Electric Potential 
24.1 – Potential Difference and Electric Potential 
24.2 – Potential Differences in a Uniform Electric Field 
24.3 – Electric Potential and Potential Energy – Point Charges 
24.4 – Obtaining E From the Electric Potential 
24.5 – Electric Potential Due to Continuous Charge Distributions 
24.6 – Potential of a Charged Conductor 

Capacitance and Dielectrics 
25.1 – An Introduction to Capacitance 
25.2 – Calculation of Capacitance 
25.3 – Combining Capacitors 
25.4 – Energy Stored in a Charged Capacitor 
25.5 – Capacitors with Dielectrics 

Current and Resistance 
26.1 – Electric Current 
26.2 – Resistance and Ohm’s Law 
26.3 – Resistance and Temperature 
26.6 – Electrical Energy and Power 

DC Circuits 
27.1 – Electromotive Force 
27.2 – Resistors in Series and in Parallel 
27.3 – Kirchhoff’s Rules 
27.4 – RC Circuits 
27.6 – Measuring Devices 

Magnetic Fields 
28.1 – The Magnetic Field 
28.2 – Magnetic Force on a CurrentCarrying Conductor 
28.3 – Torque on a Current Loop in a Uniform Magnetic Field 
28.4 – Motion of a Charged Particle in a Magnetic Field 
28.5 – Applications of the Motion of Charged Particles in a Magnetic Field 
28.6 – The Hall Effect 

Sources of the Magnetic Field 
29.1 – The Biot Savart Law 
29.2 – The Magnetic Force Between Two Parallel Conductors 
29.3 – Ampère’s Law 
29.4 – The Magnetic Field of a Solenoid 
29.5 – Magnetic Flux 

Faraday’s Law 
30.1 – Faraday’s Law of Induction 
30.2 – Motional emf 
30.3 – Lenz’s Law 
30.4 – Induced emfs and Electric Fields 
30.5 – Generators and Motors 

Inductance 
31.1 – SelfInductance 
31.2 – RL Circuits 
31.3 – Energy in a Magnetic Field 
31.4 – Mutual Inductance 
31.5 – Oscillations in an LC Circuit 
31.6 – The RLC Circuit 

AC Circuits 
32.1 – AC Sources and Phasors 
32.2 – Resistors in an AC Circuit 
32.3 – Inductors in an AC Circuit 
32.4 – Capacitors in an AC Circuit 
32.5 – The RLC Series Circuit 
32.6 – Power in an AC Circuit 
32.7 – Resonance in a Series RLC Circuit 
32.8 – Transformers 

Electromagnetic Waves 
33.1 – Maxwell’s Equations and Hertz’s Discoveries 
33.2 – Plane Electromagnetic Waves 
33.3 – Energy Carried by Electromagnetic Waves 
33.4 – Momentum and Radiation Pressure 
33.7 – The Spectrum of Electromagnetic Waves 

The Nature of Light and the Laws of Geometric Optics 
34.1 – The Nature of Light 
34.2 – Measurements of the Speed of Light 
34.4 – Reflection and Refraction 
34.5 – Dispersion and Prisms 
34.7 – Total Internal Reflection 

Geometric Optics 
35.1 – Images Formed by Flat Mirrors 
35.2 – Images Formed by Spherical Mirrors 
35.3 – Images Formed by Refraction 
35.4 – Thin Lenses 
35.6 – (Optional) The Camera 
35.7 – (Optional) The Eye 
35.8 – (Optional) The Simple Magnifier 

Interference of Light Waves 
36.1 – Conditions for Interference 
36.2 – Young’s DoubleSlit Experiment 
36.3 – Intensity Distribution of the DoubleSlit Interference Pattern 
36.4 – Phasor Addition of Waves 
36.6 – Interference in Thin Films 

Diffraction and Polarization 
37.2 – SingleSlit Diffraction 
37.3 – Resolution of SingleSlit and Circular Apertures 
37.4 – The Diffraction Grating 
37.5 – Polarization of Light Waves 

Special Relativity 
38.1 Einstein’s Postulates 
38.2 Simultaneity and Time Dilation 
38.3 Length Contraction 
38.4 Relativistic Addition of Velocities 
38.5 Relativistic Momentum 
38.6 Relativistic Energy 

Introduction to Quantum Physics 
39.1 – Quantization of Energy 
39.2 – The Photoelectric Effect 
39.3 – Photon Energies and the Electromagnetic Spectrum 
39.4 – Photon Momentum 
39.6 – The Wave Nature of Matter 
39.7 – Probability: The Heisenberg Uncertainty Principle 
39.8 – The ParticleWave Duality Reviewed 

Atomic Physics 
40.1 – Discovery of the Atom 
40.2 – Discovery of the Parts of the Atom: Electrons and Nuclei 
40.3 – Bohr’s Theory of the Hydrogen Atom 
40.4 – X Rays: Atomic Origins and Applications 
40.5 – Applications of Atomic Excitations and DeExcitations 
40.8 – Quantum Numbers and Rules 
40.9 – The Pauli Exclusion Principle 

Radioactivity and Nuclear Physics 
41.2 – Radiation Detection and Detectors 
41.3 – Substructure of the Nucleus 
41.4 – Nuclear Decay and Conservation Laws 
41.5 – HalfLife and Activity 
41.6 – Binding Energy 
