Real numerical simulations you can nudge and watch respond — a spring-mass system across every damping regime, pendulums from predictable to chaotic, and a block sliding down an incline exactly as friction says it should.
A second-order system across all four damping regimes — set the mass, spring and damping, and watch the step response ring, settle, or crawl.
Snell's law, critical angle and Fresnel reflection with a live ray diagram, plus single-slit, double-slit, grating and Airy-disc patterns drawn out.
The same Lagrangian mechanics, one, two, or three links deep — from a clean predictable swing to full chaotic motion.
A block on a slope, simulated with real friction — set the angle and coefficients and watch whether it holds, slides, or slides back.
A real 2D transient heat-transfer simulation — watch a can or bottle actually cool, with live convection and radiation physics.
The classic no-drag trajectory, plus a real 3D drag + Magnus-lift golf simulator — clubs, wind, world gravity, bounce and roll.
Race two falling objects with real drag physics — recreate Apollo 15's hammer-and-feather drop on the Moon.
Enter any three of s, u, v, a and t and get the other two, with the equation used and the working shown.
Kepler's laws and the vis-viva equation, with a live animated orbit — try the ISS, geostationary, or a Molniya orbit.
Stage a rocket, watch it launch, and see if it can actually reach orbit — real vehicle presets included.
Multi-ball collisions and Newton's Cradle, from perfectly elastic to perfectly inelastic — up to 10 balls.