SHEAR stress, \(\tau \propto \frac{{
DU
}}{{dy}}\)or, \(\tau = \
MU
\times \frac{{du}}{{dy}}\), where τ = shear stress,\(\frac{{du}}{{dy}}=\frac{{d\theta}}{{dt}}\) =
RATE
of shear
STRAINS
,θ = displacement in fluid layer