A square metal plate of 10 cm side moves parallel to another plate with a velocity of `10 cm s^(-1)` , both plates immersed in water. If the viscous force is 200 dyne and viscosity of water is 0.01 poise. What is their distance apart ?

Explanation

Here, `A = 10 xx 10 = 100 cm^2 , dv = 10 cm s^(-1), eta = 0.01 "poise", F = 200` dyne
As `" " F = eta A (dv)/(dx)`
`" " dx = (eta A dv)/(F) = (0.01 xx 100 xx 10)/(200) , dx = 0.05 cm`