**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.

$\bullet$ $\eta = 8.9\times 10^{-4}$

$\bullet$ $R = 2m$

$\bullet$ $h = 1mm$

$\bullet$ $w = 2 rad/s$