Answer
$\eta = 7.9\times10^{-2}\;Pa \cdot s$.
Work Step by Step
Use equation 10–8 for the viscosity force. Use the average radius of the concentric cylinders to calculate the plate area.
$$F=\eta A \frac{v}{\mathcal{l}}$$
$$\eta = \frac{F\mathcal{l}}{Av}$$
$$\eta = \frac{(\tau/r_{in})(r_{out}-r_{in})}{(2\pi r_{av}h)\omega r_{in}}$$
$$\eta = \frac{(0.024\;m \cdot N/0.0510m)(0.002\;m)}{(2\pi (0.0520\;m)(0.120m))(5.97\;rad/s) (0.0510)}$$
$$\eta = 7.9\times10^{-2}\;Pa \cdot s$$
