🧲 Physics
Interactive physics tools: projectile motion, waves, optics, kinematics, and electrical circuits.
Simulate projectile trajectories with adjustable angle, speed, and gravity.
Open tool →Calculate voltage, current, resistance, and decode resistor color bands.
Open tool →Visualize wave interference with adjustable frequency, amplitude, and phase.
Open tool →Solve SUVAT equations for displacement, velocity, acceleration, and time.
Open tool →Ray diagram generator for converging and diverging lenses.
Open tool →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 variables | Kinematics Calculator |
| Something is launched at an angle | Projectile Motion |
| You need voltage, current, resistance or power | Ohm's Law Calculator |
| You are working with wavelength, frequency or speed | Wave Visualizer |
| You need image distance or magnification | Lens Calculator |
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.