  We establish an analogy between the motion of spring whose mass increases
linearly with time and volatile stock markets dynamics within an economic model
based on simple temporal demand and supply functions [J. Phys. A: Math. Gen.
33, 3637 (2000)]. The total system energy E_t is shown to be proportional to a
decreasing time dependent spring constant k_t. This model allows to derive
log-periodicity cos[log (t-t_{c})] on commodity prices and oscillations
(surplus and shortages) in the level of stocks. We also made an attempt to
connect these results to the Tsallis statistics parameter q based on a possible
force-entropy correlation [Physica A 341, 165 (2004)] and find that the Tsallis
second entropic term \sum_{i=1}^{W} p_i^{q}/(q-1) relates to the square of the
demand (or supply) function.
