Question

There is a 1mm thick layer of glycerine between a flat plate of area `100cm^(2)` and and a big plate. If te coefficient of viscosity of glycerine is `1.0kg//m-sec`, then how much force is required to move the plate with a velocity of 7 cm/sec.
A. `3.5N`
B. `0.7N`
C. `1.4N`
D. None

Answer 1

Correct Answer - B
`F=etaA(dv)/(dx)" "impliesF=(1xx10^(-2)xx7xx10^(-2))/(10^(-3))impliesF=0.7N`