Problem $4(2$ points$)($category: velocity fields$)$: Calculate the location of the stagnation point in the

following velocity field $($do not neglect z$).$ vec$(V)=(u,v)=(-0\mathrm{.}781-3\mathrm{.}25x)vec()+(-3\mathrm{.}54+3\mathrm{.}25y)vec()$

Problem $5(3$ points$)($category: acceleration field$)$: A steady incompressible, two$-$dimensional velocity

field is given by the following components in the xy$-$plane:

$u=0\mathrm{.}205+0\mathrm{.}97x+0\mathrm{.}851y$

$v=-0\mathrm{.}509+0\mathrm{.}953x-0\mathrm{.}97y$

Calculate the acceleration field by finding expressions for acceleration components $a_x,a_y$ and $a_z($make

sure to simplify!$)$ and calculate the acceleration at the point $(x,y)=(2,1\mathrm{.}5).$