A Plate at a distance of 1 mm from a  moves at 60 cm/sec and requires a force of 2 N per unit area i.e. 2 N/m² to maintain speed. Determine fluid viscosity between the plates.

Concept:

According to newton's law of viscosity-

This law states that the shear stress () on a fluid element layer is directly proportional to the rate of shear strain. The constant of proportionality is called the coefficient of viscosity.

Where  shear stress 

 dynamic viscosity

 velocity gradient

Calculation:

Given data:

Distance between plates (y) = 1 mm or 1 × 10-3 m

Velocity of moving plate () = 60 cm/s or 0.6 m/s

Force per unit area on plate (F/A) = 2 N/m2

Dynamic viscosity (μ) =?