A shaft $8\mathrm{.}0$ cm in diameter is being pushed

axially through a bearing sleeve $8\mathrm{.}0+0\mathrm{.}03cm$

in diameter and $25\mathrm{.}0$ cm long. The clearance,

assumed uniform, is filled with oil whose

properties are kinematic viscosity $=0\mathrm{.}003$

$\frac{m^2}{s}$ and specific gravity$=0\mathrm{.}88$ with respect

to water at $20$C$.$ Estimate the force required

in $N$ to pull the shaft at a steady velocity of

$0\mathrm{.}4\frac{m}{s}.$