A $25-$mm$-$diameter shaft is pulled through a cylindrical bearing as shown in the

figure below. The lubricant that fills the gap between the shaft and bearing is an oil

having a kinematic viscosity of $8\mathrm{.}5{10}^{-4}\frac{m^2}{s}$ and a specific gravity of $0\mathrm{.}95.$ If the

force, $P,$ required to pull the shaft at a velocity of $3\frac{m}{s}$ is $10N,$ determine the

height of the gap between the bearing and the shaft. Assume that the velocity

distribution is linear.