The area is incorrect $\mathrm{.}1$x$\mathrm{.}3=\mathrm{.}03$m$^2$ and $\mathrm{.}1.$x$4=\mathrm{.}04$m$^2$ In additon there are two types of accelration that contribute to total accleration. Convective and local accleration for part one you just have to use convective but for part two both types must be considered.