dx method Null safety
- double time
override
    The velocity of the object in the simulation at the given time.
Implementation
@override
double dx(double time) => clampDouble(simulation.dx(time), dxMin, dxMax);The velocity of the object in the simulation at the given time.
@override
double dx(double time) => clampDouble(simulation.dx(time), dxMin, dxMax);