  A new varying-$c$ cosmological model constructed using two additional
assumptions, which was introduced in our previous work, is briefly reviewed and
the dynamic equation of the model is derived distinctly from a semi-Newtonian
approach. The results of this model, using a $\Lambda$ term and an extra
energy-momentum tensor, are considered separately. It is shown that the
Universe began from a hot Big Bang and expands forever with a constant
deceleration parameter regardless of its curvature. Finally, the age, the
radius, and the energy content of the Universe are estimated and some
discussion about the type of the geometry of the Universe is provided.
