It has been shown in [Frauenfelder, 2023] that the bounded component of the
energy surface of the planer Stark problem after the Levi-Civita transformation
are concave toric domains. In this paper, we present a different approach on
the problem of determining concave toric domains in a family of integrable
natural mechanical problems in the plane based on the computation of
action-variables. We give criteria on the potentials for the bounded components
of the energy hypersurfaces to be concave toric domains and apply these
criteria to a class of problems.Comment: 12 pages, no figur