Longitudinal motion: m·dv/dt = Fdrive − Fbrake − mg sin θ − Crr·mg cos θ − ½ρCdAv². Traction uses |F| ≤ μN, N = mg cos θ. Steering uses a bicycle-model yaw rate v tan δ / L.
Static side-tip angle φcrit = atan(track / (2 hCOM)). Lateral roll estimate atan(v² tan δ / (Lg)) plus payload shift. Suspension uses m/4 · y″ + c y′ + k y = 0 around a moving target. Analytic braking distance d = v²/(2μg).
Assumptions: planar rigid chassis, one lumped suspension mode, no terrain mesh collision solver, no drivetrain gears, no real tyre relaxation, approximate energy and stability; not suitable for engineering certification. Physics fixed at 120 Hz, renderer interpolates visually only.