Answer
$286\,\text{N}$
Work Step by Step
$\begin{array}{c}{{P=\tau A}}\\ {{A=\pi D\ell}}\end{array}$
$\tau=\mu{\frac{V}{b}}$
$P=\left(\mu{\frac{V}{b}}\right)(\pi D l)$
$\mu=\nu\rho=\nu(s G)(\rho).$
$\begin{array}{r l}{P}&{{}={\frac{(8.0\times10^{-4})(0.91\times10^{3})(3)(\pi)(0.025\,{\mathrm{m}})(0.5\,{\mathrm{m}})}{(0.0003\,)}}=\,286\,{\mathrm{N}}}\end{array}$
