Class 11

Physics

Mechanics

Mechanical Properties of Fluids

The velocity of water in a river is 18 km/hr near the surface .If the river is 5 m deep, find the shearing stress between the horizontal layers of water.The co-efficient of viscosity of water=$10_{−2}$ poise.

- $10_{−1}N/m_{2}$
- $10_{−2}N/m_{2}$
- $10_{−3}N/m_{2}$
- $10_{−4}N/m_{2}$

viscous force = $−ηAdxdv $

Shearing stress = $AF =ηdxdv $

$=10_{−2}×3600×518×1000 $

$=10_{−2}N/m_{2}$

Hence (b) option is the correct answer.