Question

A metal plate $0.2m^2$ in area is lying on a liquid layer of thickness ${10}^3$m and coefficient of viscosityof 12 decaposie. Calculate the horizontal force required to move the plate with a speed of 0.025$m^{-1}$

Answer 1

Given,

$A=0.2m^2$

$x={10}^{3}m$

$v=0.025m/s$

$\eta =12decapoise=12\times 10=120poise$

The Horizontal force required to move the plate,

$f=\eta A\frac{v}{x}$

$f=120\times 0.2\times \frac{0.025}{{10}^3}$

$f=6\times {10}^{-4}N$