Fluid Mechanics Viscosity Question 129

Question: A square plate of 0.1 m side moves parallel to a second plate with a velocity of O. 1 m/s, both plates being immersed in water. If the viscous force is 0.002 N and the coefficient of viscosity is 0.01 poise, distance between the plates in m is

Options:

A) 0.1

B) 0.05

C) 0.005

D) 0.0005

Show Answer

Answer:

Correct Answer: D

Solution:

[d] $ A={{(0.1)}^{2}}=0.01m^{2},\eta =0.01 $ poise = 0.001 decapoise (M.K.S. unit), $ dv=0.1m/s $ and $ F=0.002N $ $ F=\eta A\frac{dv}{dx} $ $ \therefore dx=\frac{\eta Adv}{F}=\frac{0.001\times 0.01\times 0.1}{0.002}=0.0005m $