Water at room temperature is between two parallel plates. The top plate is pulled at a relative

velocity of $0\mathrm{.}4\frac{m}{s}$ greater than the bottom plate.

a$.$ How far apart should the two plates be placed so that the shear stress $$ is $0\mathrm{.}30$ Pa $?$

Also, calculate the shear rate.

b$.$ If oil with a viscosity of $2{10}^{-2}$ Pa$.$s is used instead of water at the same plate spacing

and velocity as part $($a$),$ what are the shear stress and the shear rate?