Physics Calculator

📖 What this does

This calculator puts the physics formulas you meet in high school and college straight into your browser, no internet needed. It covers four sections — Mechanics & Motion, Electricity & Circuits, Heat & Gases, Optics & Waves — with more than twenty everyday scenarios: uniformly accelerated motion, free fall, Newton's second law, work and power, kinetic and potential energy, momentum and impulse, projectile motion, circular motion, plus Ohm's law, electric power, series/parallel resistors, resistivity, energy billing, heat and specific heat, thermal expansion, the ideal gas law, thermal efficiency, thin lenses, Snell's law, wave speed and the speed of sound in air. Instead of hunting for the formula and working backwards with a handheld calculator, you type in what you know and get the answer directly.

✨ Features

• Kinematics & free fall: enter initial velocity, acceleration and time to get final velocity and displacement at once; free fall works from time to height or from height back to time and impact speed.
• Newton's second law: force, mass and acceleration — give any two, get the third, with units attached.
• Work, energy & momentum: work from force and displacement with power in the same step; kinetic energy from mass and speed, potential energy from height; momentum and impulse side by side.
• Projectile & circular motion: launch speed and angle produce range, maximum height and flight time; circular motion gives linear speed, centripetal acceleration and the required centripetal force.
• Electricity toolbox: Ohm's law solves any of V/I/R; power covers P=VI, P=I²R and P=V²/R; series/parallel resistors accept any number of values; resistivity and energy billing are one click away.
• Heat & gases: heat Q=cmΔT solves any of the four quantities; linear expansion, the ideal gas law PV=nRT with any quantity solved, and thermal efficiency, with constants built in (g=9.8, R=8.314).
• Optics & waves: the thin-lens equation 1/f=1/u+1/v solves any of f/u/v; refraction detects total internal reflection and prints the critical angle; wave speed v=fλ solves any of the three; sound speed converts with temperature.

🛠 How to use

1. Open the plugin and find your scenario in the matching section (for example "Newton's second law").
2. Fill in the known quantities, using the unit shown next to each field (such as m/s, kg, N).
3. For sections with a "Solve for" dropdown (Ohm's law, heat, ideal gas), pick the quantity you want first, fill in the rest, and leave the target field empty.
4. Press Calculate and the result appears below the inputs with its unit; change the numbers and calculate again for a new set.
5. Every field comes pre-filled with a common example value, so you can press Calculate right away, or clear everything and enter your own problem.

⚠️ Notes

• Keep units consistent: use one unit system (SI) within a section — metres for length, seconds for time, newtons for force. Mixing units gives wrong answers.
• Angles are in degrees: the launch angle and the incident angle are entered in degrees; no conversion to radians is needed.
• Temperature units differ: the ideal gas law requires kelvin (K), while the sound-speed section uses Celsius (℃). Do not mix them.
• Leave the target empty: when using "Solve for", leave the target quantity's field blank and fill the other known fields before calculating.
• Total internal reflection: when light goes from a denser to a rarer medium past the critical angle, the tool reports "total internal reflection" — there is no refracted ray, which is the correct physics.