A river `10 m` deep is flowing at `5ms^(-1)`. The shearing stress between the horizontal layers of the river is (`eta=10^-(3) SI` units)

Options

A. `0.6xx10^(-3) Nm^(-2)`
B. `0.8xx10^(-3) Nm^(-2)`
C. `0.5xx10^(-3) Nm^(-2)`
D. `10^(-3) Nm^(-2)`

Answer

C

Explanation

v= 5 m/s, Strain rate =`v/l`
Coefficient of `eta = ("Shearing stress")/("Strain rate")`
Shearing stress = `eta xx` Strain rate
`= 10^(-3) xx (5)/(10) =0.5xx10^(-3) N//m^2`.