raatools/

🧲 Fysikk

Interaktive fysikkverktøy: prosjektilbevegelse, bølger, optikk, kinematikk og elektriske kretser.

Mechanics, optics and circuit theory — the standard calculations from an introductory physics course, with the working shown so you can follow the method rather than copy an answer.

Most of these have a diagram alongside the numbers, because the point where these problems go wrong is usually the setup rather than the algebra: a sign convention, an angle measured from the wrong axis, a component resolved the wrong way.

Which tool do I want?

If you…Use
Constant acceleration, and you know three of five variablesKinematikkalkulator
Something is launched at an angleProsjektilbevegelse
You need voltage, current, resistance or powerOhms lov-kalkulator
You are working with wavelength, frequency or speedBølgevisualiserer
You need image distance or magnificationLinsekalkulator

Pick a positive direction and hold it

Nearly every wrong SUVAT answer is a sign error rather than an arithmetic one. The equations do not know which way is up; you have to decide, and then stay consistent for every quantity in the problem.

Take a ball thrown upward at 20 m/s. Call up positive and gravity is −9.81 m/s², so at the top the velocity is zero and the displacement is positive. Call down positive and the initial velocity is −20 with gravity at +9.81. Both give the same physical answer. Mixing them — a positive initial velocity with positive gravity — gives a ball that accelerates upward forever.

The same discipline covers displacement versus distance. Throw a ball up and catch it and the displacement is zero while the distance travelled is twice the peak height. SUVAT solves for displacement, so a zero is often correct and simply not the number you wanted.