The bouncing discs (left box) conserve total kinetic energy and momentum in elastic collisions. The glowing bar (right) is a renewable resource stock following logistic growth minus harvest — the same conservation-of-mass bookkeeping used in fisheries and forestry management.
Elastic collision: Σ(½mv²) = const, Σ(mv) = const
Resource: dS/dt = r·S·(1 - S/K) - H
- Particle count — number of discs conserving energy/momentum in the collision box.
- Restitution — fraction of kinetic energy kept per collision (1 = perfectly elastic).
- Harvest rate — fraction of the resource stock removed per second (extraction).
- Regrowth rate — intrinsic growth rate r of the logistic resource model.
Real-world application: this same balance — inflow/regrowth vs. outflow/harvest — governs sustainable fisheries quotas and forestry rotation planning.