Answer
${\frac{d u}{d y}}=1000{s^{-1}}$
Work Step by Step
$\tau=\mu \frac{d u}{d y}$
where $\mu=1.0 \times 10^{-3} \frac{\mathrm{N} \cdot \mathrm{s}}{\mathrm{m}^2}$ and $\tau=1.0 \frac{\mathrm{N}}{\mathrm{m}^2}$
$$
\frac{d u}{d y}=\frac{\tau}{\mu}=\frac{1.0 \frac{\mathrm{N}}{\mathrm{m}^2}}{1.0 \times 10^{-3} \frac{\mathrm{N} \cdot \mathrm{s}}{\mathrm{m}^2}}=1000 [ {{s}}^{-1}]
$$
