A fluid with viscosity `eta` fills the space between two long co-axial cylinders of radii `R_1 `and
Channel: Doubtnut
Date: 2020-08-30

A fluid with viscosity `eta` fills the space between two long co-axial cylinders of radii `R_1 `and `R_2`, with `R_1 lt R_2`. The inner cylinder is stationary while the outer one is rotated with a constant angular velocity `omega_2`. The fluid flow is laminar. Taking into account that the friction force acting on a unit area of a cylindrical surface of radius r is defined by the formula `sigma=etar(delomega//delr)`, find:(a) the angular velocity of the rotating fluid is as a function of radius r, (b) the moment of the friction forces acting on a unit length of the outer cylinder.