In the physical system, dc and infinite frequency are in fact strange cases. In the case of dc, for example, a nonzero constant force implies that the mass is under constant acceleration. It is therefore the case that its velocity is linearly growing. Our simulation predicts this, since, using Eq.(F.43) and Eq.(F.42),
The dc term is therefore accompanied by a linearly growing term in the physical mass velocity. It is therefore unavoidable that we have some means of producing an unbounded, linearly growing output variable.
Mass-Spring Boundedness in Reality
A Signal Processing Perspective on Repeated Mass-Spring Poles