Question 1.7: A liquid is having the viscosity of 7.5 × 10^-4 Pa s. If the......

Given,

\text { Viscosity, } \mu=7.5 \times 10^{-4}

\text { Strain rate, }\left\lgroup \frac{d \theta}{d t} \right\rgroup =5000  s ^{-1}

From Newton’s law of viscosity,

\tau=\mu \frac{d u}{d y}

So, we know that the velocity gradient is equal to strain rate.

\begin{aligned} \frac{d u}{d y} & =\frac{d \theta}{d t} \\ \tau & =\mu \frac{d \theta}{d t} \\ & =0.0075 \times 5000 \\ & =3.75  Pas \end{aligned}