Fluid Mechanics Viscosity Question 309
Question: The velocity of water in a river is 18 km/hr near the surface. If the river is 5m deep, find the shearing stress between the horizontal layers of water. The co-efficient of viscosity of water$ ={{10}^{-2}}poise $ .
Options:
A) $ {{10}^{-1}}N/m^{2} $
B) $ {{10}^{-2}}N/m^{2} $
C) $ {{10}^{-3}}N/m^{2} $
D) $ {{10}^{-4}}N/m^{2} $
Show Answer
Answer:
Correct Answer: B
Solution:
[b] $ \eta ={{10}^{-2}},poise $ $ v=18km/h=\frac{18000}{3600}=5m/s $ $ l=5m $ Strain rate$ =\frac{v}{l} $ $ Coefficient,of,vis\cos ity,\eta =\frac{shearing,stress}{strain,rate} $ $ \therefore ,,,Shearing,stress=\eta \times strain,rate $ $ ={{10}^{-2}}\times \frac{5}{5}={{10}^{-2}}N{{m}^{-2}} $
BETA
