Coulomb used the following method to determine the viscosity of liquids. A thin plate of weight \(W\) is suspended vertically and set into motion, first in air and then fully submerged in the particular liquid as shown in Figure 3.54. The time duration, \(t_{1}\) in air and \(t_{2}\) in the liquid, required for one oscillation is measured. The frictional force between the plate and fluid is estimated as \(2 A c v\), where \(2 A\) is the area of both sides of the plate, \(c\) is the coefficient of viscosity, and \(v\) is the plate velocity. The frictional force between the plate and air is negligible. Find the value of \(c\) in terms of the above parameters.

Transcribed Image Text:

W k Figure 3.54: Plate suspended in a liquid.