Question

The relative velocity of two consecutive layers is $8cm/s$. If the perpendicular distance between the layers is $0.1cm$, then the velocity gradient will be

• A. $8c{m}^{-1}$
• B. $80c{m}^{-1}$
• C. $0.8c{m}^{-1}$
• D. $0.08c{m}^{-1}$

Answer 1

Answer: (B)

$80c{m}^{-1}$

velocity gradient $=\frac{dv}{dx}$, where $dv$ is relative velocity of two consecutive layers, and $dx$ is the perpendicular distance between the layers
$\Rightarrow$ velocity gradient $=\frac{dv}{dx}=\frac{8}{0.1}=80c{m}^{-1}$