A cylinder of 100 mm diameter and 300 mm
length rotates about a vertical axis inside a
fixed cylindrical tube of 105 mm diameter and
300 mm length. If the space between the tube
and the cylinder is filled with liquid of dynamic
viscosity of 0.125 N.s/mº, determine the speed
of rotation of the cylinder which will be obtained
if an external torque of 1 Nm is applied to it
[Ans. 81.03 r.p.m.)