d
\(\begin{array}{l}
s = \frac{{{t^2}}}{3};\frac{{ds}}{{dt}} = \frac{{2t}}{3};\frac{{{d^2}s}}{{d{t^2}}} = \frac{2}{3}\\
Work\,done,\,W = \int {Fds\, = \int {m\frac{{{d^2}s}}{{d{t^2}}}ds} } \\
 = \int {m\frac{{{d^2}s}}{{d{t^2}}}\frac{{ds}}{{dt}}dt = \int\limits_0^2 {3 \times \frac{2}{3} \times \frac{{2t}}{3}dt = \frac{4}{3}\int\limits_0^2 {tdt} } } \\
 = \frac{4}{3}\int\limits_0^2 {tdt}  = \frac{4}{3}\left| {\frac{{{t^2}}}{2}} \right|_0^2 = \frac{4}{3} \times 2 = \frac{8}{3}\,J.
\end{array}\)