Question

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

• A. $ 50\text{ }{{s}^{-1}} $
• B. $ \text{60 }{{s}^{-1}} $
• C. $ \text{75 }{{s}^{-1}} $
• D. $ \text{80 }{{s}^{-1}} $

Answer 1

Answer: (D)

Velocity gradient $ =\frac{\Delta v}{\Delta y} $
where $ \Delta v $ is relative velocity between the layers and $ \Delta y $ is distance between the layers.
Therefore velocity gradient $ =\frac{8.0}{0.1}=80.0\,{{s}^{-1}} $