(c) From work energy theorem, $\mathrm{\Delta}\ KE\ = W_{net}$
$K_{f} - K_{i} = \int_{}^{}{P\ dt}$
$\frac{1}{2}mv^{2} - 0 = \int_{0}^{2}\left( \frac{3}{2}t^{2} \right)dt\ or\ \frac{1}{2}(2)v^{2} = \frac{3}{2}\left\lbrack \frac{t^{3}}{3} \right\rbrack_{0}^{2} = 4$
$v = 2\ ms^{- 1}$