A plate 10 mm distant from a fixed plate moves at 2 m/s and requires a force of 300 N/m² to maintain this speed. Determine dynamic viscosity of the fluid between the plates,

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 Q. A plate 10 mm distant from a fixed plate moves at 2 m/s and requires a force of 300 N/m² to maintain this speed. Determine dynamic viscosity of the fluid between the plates,

SOLUTION:
Shear stress τ=μ * dv/dy
τ = 300Nm^2
dv = change of velocity = 2m / s
dy = distance between the plates = 10mm = 0.01m .
By substituting in the above equation.
300 = μ * 2/0.01
Dynamic viscosity μ = 300 * 0.01/ 2
=1.5 N-Sm²

Q. A plate 20 mm distant from a fixed plate moves at 3 m/s and requires a force of 200 N/m² to maintain this speed. Determine dynamic viscosity of the fluid between the plates,

SOLUTION:
Shear stress τ=μ * dv/dy
τ = 200Nm^2
dv = change of velocity = 3m / s
dy = distance between the plates = 20mm = 0.02m .
By substituting in the above equation.
200 = μ * 3/0.02
Dynamic viscosity μ = 200 * 0.02/ 3
=1.33 N-Sm²

Q. A plate 40 mm distant from a fixed plate moves at 4 m/s and requires a force of 400 N/m² to maintain this speed. Determine dynamic viscosity of the fluid between the plates,

SOLUTION:
Shear stress τ=μ * dv/dy
τ = 400Nm^2
dv = change of velocity = 4m / s
dy = distance between the plates = 40mm = 0.04m .
By substituting in the above equation.
400 = μ * 4/0.04
Dynamic viscosity μ = 400 * 0.04/ 4
=4 N-Sm²

DEFINITIONS

DYNAMIC VISCOSITY: IT’S  RATIO BETWEEN THE KINEMATIC VISCOSITY AND THE MASS DENSITY

KINEMATIC VISCOSITY:

IT’S  RATIO BETWEEN THE DYNAMIC VISCOSITY AND THE MASS DENSITY

 

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