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.

Question

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. (A) 10-1 N/m2 (B) 10-2 N/m2 (C) 10-3 N/m2 (D) 10-4 N/m2

Tardigrade Admin · Accepted Answer

Velocity of a layer of water, V =(5/18) 18=5 m / s Also, η=10-2 poise =10-3 ( Ns / m 2) Shear stress, τ=η ( V / d )=10-3 X 5 / 5=10-3 ( N / m 2)

Q. The velocity of water in a river is $18 km / h r$ 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 $= 1 0^{- 2}$ poise.

$1 0^{- 1} N / m^{2}$

$1 0^{- 2} N / m^{2}$

$1 0^{- 3} N / m^{2}$

$1 0^{- 4} N / m^{2}$

Velocity of a layer of water, $V = \frac{5}{18} 18 = 5 m / s$
Also, $η = 1 0^{- 2}$ poise $= 1 0^{- 3} \frac{N s}{m ^{2}}$
Shear stress, $τ = η \frac{V}{d} = 1 0^{- 3} X 5/5 = 1 0^{- 3} \frac{N}{m ^{2}}$

Q. The velocity of water in a river is 18km/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.

10−1N/m2

10−2N/m2

10−3N/m2

10−4N/m2