raatools/

🧲 Physique

Outils de physique interactifs : mouvement de projectile, ondes, optique, cinématique et circuits électriques.

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 variablesCalculateur de cinématique
Something is launched at an angleMouvement de projectile
You need voltage, current, resistance or powerCalculateur loi d'Ohm
You are working with wavelength, frequency or speedVisualiseur d'ondes
You need image distance or magnificationCalculateur de lentilles

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.