The shear stress at a point in a liquid is found to be 0.03 N/m2. The velocity gradient at the point is 0.15 s-1. What will be it’s viscosity (in Poise)?

Tresca or maximum-shear stress criteria assumes that yielding occurs when the maximum shear stress reaches a value of the shear stress in the uniaxial tension test. Assume the principal stress being σ1, σ2, σ3 where σ1 is largest, and σ3 is the smallest principal stresses. Find the value of minimum shear stress to cause yielding, given that yield stress in tension is equal to σo?

A

τ = σo

B

τ = σo/2

C

τ = σo/3

D

τ = σo/4

In Newton's law of viscosity, which states that the shear stress is proportional to the __________ Co-efficient of viscosity is called dynamic or absolute viscosity(where, V = velocity, Vg = velocity gradient ).

A

V²

B

1/V²

C

1/Vg

D

Vg

In Newton's law of viscosity, which states that the shear stress is proportional to the __________ co-efficient of viscosity is called dynamic or absolute viscosity (where, V = velocity, $${{\text{V}}_{\text{g}}}$$ = velocity gradient).

A

V²

B

$$\frac{1}{{{{\text{V}}^2}}}$$

C

$$\frac{1}{{{{\text{V}}_{\text{g}}}}}$$

D

V_g

The Rheological behaviour of concrete, when represented by shear stress vs rate of shear, is characterized as Where : τ shear stress, Τ0 = (initial) yield value, μ = at-point plastic viscosity, γ̇ = at point rate of shear.

A

τ = τ₀ + μ . γ̇

B

τ₀ = τ + μ . γ̇

C

$\frac{\tau }{{{\tau _0}}} = \mu .\dot \gamma$

D

τ = μ . γ̇

If the equation of a velocity profile over a plate is v = 5y2 + y (where v is the velocity in m/s) determine the shear stress at y = 0. Given the viscosity of the liquid is 8.35 poise.

A

0.830

B

0.832

C

0.835

D

0.834

The viscosity of a fluid in motion is 1 Poise. What will be it’s viscosity (in Poise) when the fluid is at rest?

A

0

B

0.5

C

1

D

2

The velocity distribution for fluid flow over a flat plate is given by u=2y-6y2 in which u is the velocity in metre per second at a distance of y metre above the plate. Determine the shear stress at y=0.15m.Take dynamic viscosity of fluid as 8.6 poise.

A

0.172 N/m2

B

0.344 N/m2

C

0.086 N/m2

D

None of the mentioned

How far is point 'R' from Point 'T'? Statement (I): Point 'R' is 5 metres to the north of point 'M'. Point 'U' is 4 metres to the east of point 'R'. Point 'T' is to the west of point 'R' such that points 'U' 'R' and 'T' form a straight line of metres. Statement (II): Point 'Z' is metres to the south of point 'T'. Point 'U' is metres to the east of point 'T'. Point 'M' is metres to the east of point 'Z'. Point 'R' is metres to the north of point 'M'. Point 'R' lies on the line formed by joining points 'T' and 'U'.

A

Statement (I) and (III) are independently sufficient to answer the question.

B

Statement (I) and (II) are together required to answer the question.

C

Statement (I) alone is sufficient to answer the question while statement (II) is not sufficient to answer the question.

D

Statement (II) alone is sufficient to answer (I) is not sufficient to answer the question.

Select from the following non - Newtonian fluids in which the rate of shear deformation is a function of both shear stress and time - (1) Dilatant liquid (2) Bingham plastic liquid (3) Pseudoplastic liquid (4) Thixotropic liquid (5) Rheopectic liquid

A

1, 2 and 3

B

2 and 3

C

1, 4 and 5

D

4 and 5

Angled baffles are preferred in the agitation tank to control the swirling action; if the viscosity of the liquid to be mixed is about 200 poise. However, the baffle may be completely eliminated for mixing liquids having viscoisty above __________ poise.

A

300

B

600

C

1000

D

1500

The shear stress at a point in a liquid is found to be 0.03 N/m2. The velocity gradient at the point is 0.15 s-1. What will be it’s viscosity (in Poise)?

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