A force of 19N is required to move the upper plate at a constant speed of 0.25 m/s. The area of the plate is 0.5 m? and they are separated by a distance of 1cm. (a) calculate the coefficient of the viscosity of the fluid between the two plates? (b) calculate the velocity gradient?

A torque is applied to rotate a cylindrical shaft (diameter D 1 , length L) at a constant angularspeed ω, inside a co-axial, stationary cylinder of the same length and diameter D 2. The gapbetween the bottom surface of the shaft and that of the stationary cylinder is h.(a) Develop a general expression of the torque in terms of the geometric dimensions andthe viscosity μ of an oil filling the gaps between the shaft and the stationary cylinder.Assume linear velocity profiles in all the gaps.(b) Determine the numerical value of the torque in the case of an oil of viscosity of 0.1Pa.s. [D 1=5cm, D 2=5.2cm, L=10cm, ω=50rpm, h=1mm]