When a flea $($mm $=600$ gg$)$ is jumping up$,$ it extends its legs $0\mathrm{.}5$ mmmm and reaches a speed of $0\mathrm{.}40$ m$/$sm$/$s in that time. How much work did the flea do during that time? Use gg $=10$ m$/$s$2$m$/$s$2.$