Text edition · micro-app
Physics Lab
Impulse physics sandbox, pure Dart
What it is
An interactive 2D physics sandbox: fixed-step integrator, impulse-based circle collisions with positional correction, restitution and air-drag presets, and a live kinetic-energy HUD. The engine is pure Dart, verified headlessly (momentum conservation, energy dissipation, no tunnelling) — tap to drop bodies, drag to flick them.
- Dart
- Physics
- CustomPaint
Under the hood
- Fixed-step integrator with sequential impulses: restitution, air drag and positional correction, plus a final bounds pass so bodies cannot escape walls.
- The engine is pure Dart and verified headlessly — 10 assertions cover momentum, energy dissipation, wall containment and tunnelling.
- Tap to drop bodies, drag to flick them; motion trails and a live kinetic-energy readout make the simulation observable.
Honest notes
- 2D circles only — no rotational inertia or arbitrary polygon stacking.