Solution
= Solution
The fluid shear stress is
$$
\tau_{xy}(y)=\mu u'(y)
=\frac{\mu U}{h}+G\left(y-\frac h2\right).
$$
The condition $\tau_{xy}(0)=0$ therefore gives
$$
\boxed{G_0=\frac{2\mu U}{h^2}}.
$$
= Solution
The fluid shear stress is
$$
\tau_{xy}(y)=\mu u'(y)
=\frac{\mu U}{h}+G\left(y-\frac h2\right).
$$
The condition $\tau_{xy}(0)=0$ therefore gives
$$
\boxed{G_0=\frac{2\mu U}{h^2}}.
$$