$2\mathrm{.}5\mathrm{.}10$ For laminar flow in a circular conduit use Newton's law of viscosity, ${}_0=d\frac{u}{d}y,$ where $u$ is the fluid velocity at distance $y$ from the wall, to establish that the velocity distribution in the conduit is given by $u=u_{\text{m}\text{a}\text{x}}(1-\frac{r^2}{R^2}),$ where $r$ is the distance from the center of a pipe of radius $R$ and $u_{\text{m}\text{a}\text{x}}$ is the velocity at the pipe center.