Practice Questions

20. Newton's law of viscosity relates shear stress and the rate of shear strain. It is given by the equation r = μ (du/dy)

shear stress and the rate of angular distortion

Viscosity is the measure of a fluid's resistance to deformation caused by friction within the fluid. There are two kinds of viscosity: Dynamic viscosity (μ) and Kinematic viscosity (v). Dynamic viscosity is measured in $Ns / m ^ 2$ or Pa - s or Poise, while kinematic viscosity is measured in $m ^ 2 / s$ or Stokes.

The definition of the compressible and incompressible fluid is defined according to the changes in density. Compressible fluids are fluids whose density can change significantly with changes in pressure or temperature. Incompressible fluids, on the other hand, are fluids whose density remains relatively constant with changes in pressure or temperature.

Water is a Newtonian fluid because its shear stress is linearly proportional to its shear strain rate.

Viscosity is the internal resistance of a fluid to motion. The unit of dynamic viscosity is $N. s / m ^ 2$ . Kinematic viscosity is the ratio of dynamic viscosity to density and its unit is Stoke or  $m ^ 2 / s$

Mass density represents the mass (or the number of particles) per unit volume of a substance, material, orobject. Mass density is also known as density.its SI unit is $kg/m^3$

Kinematic viscosity is the ratio of dynamic viscosity to mass density. The equation for kinematic viscosity is v = μ/ρ. Its Sl unit is m²/s and CGS unit is cm²/s or stoke.

When a fluid is at rest, it does not resist shear stress as a solid does. Any amount of shear stress applied to a fluid will cause it to move and deform continuously. Therefore, a fluid at rest must be in a state of zero shear stress.

6. hear thickening fluid, also known as Dilatant, is a type of fluid whose viscosity increases as the shear rate increases. This is in contrast to shear thinning fluids, which have a decreasing viscosity as shear rate increases.

4. Dynamic viscosity is the property of a fluid that offers resistance to the movement of one layer of fluid over an adjacent layer of the fluid. Poise is a unit of dynamic viscosity, where 1 Poise is equivalent to 0.1 N s/m2. 1 Poiseuille is equivalent to 10 Poise and 1 decapoise.

aper pulp is a type of non-Newtonian fluid known as a pseudoplastic fluid. Other examples of pseudoplastic fluids include fine particle suspensions, gelatine, blood, and polymeric solutions such as rubbers and paints. Pseudoplastic fluids have a decreasing viscosity with increasing shear rate.

Mercury does not wet the glass because of the property of the liquid known as cohesion. Cohesion refers to the attractive force between molecules of the same substance, which in the case of mercury, is stronger than the adhesive forces between mercury and glass.

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