Liquid Friction!

Classical Mechanics Level 5

A Thin circular disk of radius \(R\), rotates in a cylindrical chamber, which is filled with water (coefficient of viscosity \(\eta\)). It is rotated with constant angular velocity \(\omega\).
Find the Power developed (in watts)by the viscous forces, if the distance between the top-bottom walls and the disk is \(h\).

Details and Assumptions:
\(\bullet\) Neglect end effects.
\(\bullet\) \(\eta = 8.9\times 10^{-4}\)
\(\bullet\) \(R = 2m\)
\(\bullet\) \(h = 1mm\)
\(\bullet\) \(w = 2 rad/s\)

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