$($Problem $4\mathrm{.}28$ in Book$)$ For the two$-$dimensional velocity distribution $u=4y$ and $v=2x,($a$)$

check if the continuity is satisfied. $($b$)$ Are the Navier$-$Stokes equations valid? $($c$)$ If so$,$

determine the pressure field $p(x,y)$ if the pressure at the origin is $p_0.$