(Solved): The density of oil at 20C is 850kg/m3, find the relative density and kinematic viscosity of ...

The density of oil at $20^{?}\mathrm{C}$ is $850\mathrm{kg}/{\mathrm{m}}^3$, find the relative density and kinematic viscosity of the oil if its dynamic viscosity is $5\times 10^{?3}\mathrm{kg}/\mathrm{ms}$. b.) If the velocity distribution of a viscous liquid $(?=0.9\mathrm{Ns}/{\mathrm{m}}^2$ ) over a fixed boundary is given by $u=0.68y?y^2$ in which $u$ is the velocity in $[\mathrm{m}/\mathrm{s}]$ at a distance $y$ metres above the boundary surface, determine the shear stress at the surface and at $y=0,34\mathrm{m}$.