$\t\approx 1500$. This indicates that the MD system is able to overcome the metastability at or near $\e_{coll}$. The observed uncertainty is likely due to the relatively small number of particles.

![\[fig\_ec1\] Plots of the kinetic energy $\e_{kin}$ (top) and the virial variable $\s$ (bottom) vs time $\t$ for a system with $\e=\e_{coll}\approx-0.339$ and $N=250$.The data is averaged over $\d \t=100$ time intervals.](fig9.eps){width=".45\textwidth"}

As we increase the energy above $\e_{coll}$, the stability of the uniform state increases which results in a longer lifetime of such state with respect to collapse. In Fig. \[fig\_met\], an evolution of a system with $\e=-0.3$ is shown. The system stays in the uniform state for about $\d \t \approx 5000$ before the collapse starts, after which the evolution proceeds qualitatively similar to the collapses in systems with lower energies.

![\[fig\_met\] Plots of the kinetic energy $\e_{kin}$ (top) and virial variable $\s$ (bottom) vs time $\t$ for a system with $\e=-0.3$ and $N=250$. The data is averaged over $\d \t=100$ time intervals.](fig10.eps){width=".45\textwidth"}

To compare the temporal evolution of the kinetic energy, virial variable, and the number of core particles, the relative variables $\e'_{kin}(\t)$, $\s'_{kin}(\t)$, and $N'_{core}(\t)$, all defined as $\e'_{kin}(t)=[\e_{kin}(t)-\e_{kin}(u)]/[\e_{kin}(c-h)-\e_{kin}(u)]$, are plotted in Fig.\[fig\_ec\]. The values 