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’di-pen’dənt). adj.  1. Free from the influence or control of others. a) free from the rule of another; b) free from persuasion or bias; self-determined; self-reliant, 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 ever-growing 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.

Explore Demo

Seeing is Believing

Explore our library and other great features in our demo.

Explore Demo

Key Benefits of our Library

  • Multi-step problems authored and individually vetted by physics experts
  • Each problem independently peer-reviewed
  • Largest collection of symbolic problems available on the market
  • Five levels of difficulty to match your course
  • Algebra-based, calculus-based, and conceptual-based problems
  • Varied complexity, including  quick, one-to-two part questions, multi-step questions, and more involved problems that capture more of the students’ work
  • Randomized numbers and phrases for the majority of our problems
  • Our ever-expanding 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 well-written 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 first-hand 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.

  1. 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
  2. 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
  3. 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
  4. 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
  5. 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:

  1. 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
  2. Algebra (Alg): These are problems appropriate for algebra-based classes. No calculus ability is required.
    Algebra Problem Example
  3. Calculus (Calc): These problems are appropriate for calculus-based classes. This does not mean that the problem will always involve calculus, but it may include parts that are not appropriate for an algebra-based 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
2.1 – Coordinate Systems
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
3.2 – Instantaneous Velocity and Speed
3.3 – Acceleration
3.4 – Motion Diagrams
3.5 – One-Dimensional Motion with Constant Acceleration
3.6 – Objects in Free Fall
2D Motion
4.1 – Displacement, Velocity and Acceleration Vectors
4.2 – Two-Dimensional 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
5.2 – Mass
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
5.8 – Free body diagram drawings (equilibrium)
5.9 – Free body diagram drawings (net acceleration)
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 Work-Kinetic 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 Work-Energy
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 – Two-Dimensional Collisions
9.6 – The Center of Mass
9.8 – Rocket Propulsion
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 (Cross-products)
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
12.2 – More on the Center of Gravity
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
13.6 – Damped Harmonic Motion
13.7 – Driven Harmonic Motion and Resonance
14.1 – Newton’s Law of Universal Gravitation
14.2 – Measuring the Gravitational Constant
14.3 – Free-Fall 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
15.8 – Surface Tension and Capillary Action
Mechanical Waves
16.1 – Basic Variables of Wave Motion
16.3 – One-Dimensional Traveling Waves
16.4 – Superposition and Interference
16.5 – The Speed of Waves on Strings
16.7 – Sinusoidal Waves
16.8 – Rate of Energy Transfer by Sinusoidal Waves
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
17.6 – Sound and Hearing
17.7 – Ultrasound
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
19.2 – Thermometers and Temperature Scales
19.3 – The Constant-Volume Gas Thermometer and the Kelvin Scale
19.4 – Thermal Expansion of Solids and Liquids
19.5 – Macroscopic Description of an Ideal Gas
19.6 – The Kinetic Theory of Gases
19.7 – Vapor Pressure and Partial Pressure
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
21.9 – Entropy on a Microscopic Scale
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
26.5 – A Model for Electrical Conduction
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 Current-Carrying 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
30.7 – Maxwell’s Equations
31.1 – Self-Inductance
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
33.6 – The Production of Electromagnetic Waves by an Antenna
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 Double-Slit Experiment
36.3 – Intensity Distribution of the Double-Slit Interference Pattern
36.4 – Phasor Addition of Waves
36.6 – Interference in Thin Films
Diffraction and Polarization
37.2 – Single-Slit Diffraction
37.3 – Resolution of Single-Slit 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
39.5 – The Particle-Wave Duality
39.6 – The Wave Nature of Matter
39.7 – Probability: The Heisenberg Uncertainty Principle
39.8 – The Particle-Wave 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 De-Excitations
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 – Half-Life and Activity
41.6 – Binding Energy
Medical Applications of Nuclear Physics
42.2 – Biological Effects of Ionizing Radiation
42.3 – Therapeutic Uses of Ionizing Radiation
42.5 – Fusion
Particle Physics
43.3 – Accelerators Create Matter from Energy
43.4 – Particles, Patterns & Conservation Laws
Frontiers of Physics
44.1 – Cosmology & Particle Physics