PROBLEM $2\mathrm{.}7$:

In a flowing fluid, the speeds of two layers that have $1cm$ spacing between them are $U_1=2c\frac{m}{s}$ and $U_2=3c\frac{m}{s},$ respectively. Find the shear stress in this region in terms of

$\frac{N}{m^2}*({}_{\text{o}\text{i}\text{l}}=0\mathrm{.}8k\frac{N}{m^3}$;$v_{\text{o}\text{i}\text{l}}=1{10}^{-4}\frac{m^2}{s})$