Physics Formula Library
This formula library is the canonical study surface for equations used across mechanics, waves, electricity, thermodynamics, relativity, and modern physics. A formula is included here only when the page can explain what the symbols mean, when the equation applies, and what assumptions sit behind the compact notation.
How to read a formula
A physics formula is not a magic sentence. It is a compressed model of a physical situation. Before using one, identify the system, the interval of time, the coordinate direction, and the quantities that are being treated as constant. Then check the units. If both sides of the equation do not have the same dimensions, the equation has been copied incorrectly or used outside its intended context.
For example, F = m a describes net force, not every individual applied force. KE = 1/2 m v^2 describes translational kinetic energy at ordinary speeds. W = F d is a simplified work equation for constant force along the displacement; the more general version uses the force component parallel to motion, and advanced courses replace the product with an integral when force changes with position.
Core formula groups
Mechanics: displacement, velocity, acceleration, force, momentum, impulse, work, power, kinetic energy, gravitational potential energy, torque, angular velocity, and centripetal acceleration.
Waves and optics: wave speed, frequency, wavelength, Snell's law, lens equations, interference path difference, diffraction spacing, intensity, and decibel scale.
Electricity and magnetism: Ohm's law, electric power, Coulomb's law, electric field, electric potential, capacitance, magnetic force, Faraday's law, inductance, and RC/RL time constants.
Thermal and modern physics: ideal gas law, heat transfer, specific heat, half-life, photon energy, de Broglie wavelength, relativistic momentum, time dilation, and Schwarzschild radius.
Using the library for homework and revision
- Start with the concept, not the equation list.
- Choose the equation whose assumptions match the problem statement.
- Write every value with a unit before substituting.
- Check the result by estimating its order of magnitude.
- Use the calculator pages only after you understand the model.
Selected formula tools
Formula quality checklist
Every formula entry should eventually answer the same set of reader questions. What physical quantity is being calculated? What are the symbols and SI units? Which assumptions make the equation valid? What is a simple worked example? What mistake do students most often make with it? If a formula page cannot answer those questions, it should remain a support page rather than a monetized standalone guide.
This standard is especially important for equations that look similar but describe different situations. Work, power, energy, force, pressure, and momentum are often confused because their everyday meanings overlap. The formula library is designed to separate those ideas by connecting each equation to units, examples, and limitations.
Dimensional analysis
Dimensional analysis is the formula library's built-in error check. Force has dimensions of mass times acceleration. Energy has dimensions of force times distance. Pressure has dimensions of force per area. When students learn to inspect dimensions, they can often detect the wrong equation before doing any arithmetic.
Editorial inventory note
This page is part of the approved reader-facing inventory because it now provides context, assumptions, and maintenance standards rather than a bare list or generated template. Future edits should preserve that standard: keep the page useful as a standalone learning resource, keep ads away from thin support URLs, and return excluded pages to the sitemap only after a real rewrite adds specific examples, definitions, and explanation.
The practical test is reader value. A visitor should be able to land here, understand what the page is for, learn how to use it, and see how it connects to the broader physics library without needing to open a dozen near-duplicate pages.
How to use the formula library for ranking-level study
A useful physics formula page should do more than name an equation. The reader needs to know the physical system, the assumptions that make the equation valid, the meaning of each symbol, the unit check, and the limiting cases that reveal whether the result is reasonable.
Use this library by first identifying the topic area, then opening the formula detail or calculator that matches the problem. Before substituting numbers, write the units beside every variable and ask whether the model assumes constant acceleration, no friction, a linear material, a closed system, a weak field, or another simplifying condition.
The strongest pages in the library connect equations to examples. A force formula should lead to free-body diagrams, an energy formula should explain conservation and loss terms, and an electromagnetic formula should clarify field direction as well as magnitude.
For exam preparation, pair this page with the calculator hub, glossary, and common mistake guides. That route turns formulas from memorized fragments into a working method for solving unfamiliar physics problems.