Fluid Mechanics
1. A fluid is the one, which 8.
(a) cannot remain at rest under the action of shear force.
(b) continuously expands till it fills any con- tainer.
(c) is incompressible.
(d) permanently resists distortion.
2. In an incompressible fluid, the density is 9.
(a) greatly affected by moderate changes in pressure.
(b) greatly affected only by moderate changes in temperature.
(c) not affected with moderate change in temWith increase in the
temperature,
viscosity of 1a liquid
(a) increases
(b) decreases
(c) remains constant
(d) may increase or decrease; depends on the
liquid
For water, when the pressure increases, the viscosity
(a) also increases
(b) decreases
(c) remains constant
(d) first decreases, and then increases
perature & pressure. 10. For a fluid rotating at constant angular veloc-(d)
sensible to
changes in both temperature & ity about vertical axis as a rigid body, the prespressure. sure
intensity varies
as the
,3. Potential flow is characterized by the (a) (a) irrotational and
frictionless flow.
(b) (b) irrotational and frictional flow. (c) (c) one in which dissipation
of
mechanical en(d)
ergy into heat occurs. 11. The centre of pressure is(d) formation of eddies within
the stream.
(a)
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4. Newton’s law of viscosity relates the (b)
always below the centroid of the area. always above the centroid of
the area.
(a) shear stress and velocity. (c) a point on the line of action of the
resul(b)
velocity gradient and pressure intensity. tant force.
(c) shear stress and rate of angular deforma(d) at the centroid of the
submerged
area.
tion in a fluid. 12. A stream tube is that, which has.....cross-sec(d) pressure
gradient and rate
of angular detion entirely bounded by stream lines.formation. (a) a circular (b) any
convenient
5. Dimension of absolute viscosity is (c) a small (d) a large
(a) ML–1T–1 (b) MLT–1 Mass velocity is independent of temperature & (c)
ML–1T (d)
MLT 13.
square of the radial distance. radial distance linearly.
inverse of the radial distance. elevation along vertical direction.
,6.
pressure, when the flow is Poise is converted into stoke by (a)
(a) multiplying with density (gm/c.c.). (b)
(b) dividing by density (gm/c.c.).
(c) Multiplying with specific gravity. (c)
unsteady through unchanged cross-section. steady through changing
unchanged
crosssection. steady and the cross-section is changed.
(d) dividing by specific gravity.14. In turbulent flow, the
7. Dimension of kinematic viscosity. (a) fluid particles move in an
orderly
manner. (a) MLT–1 (b) L2 . T–1 (b) momentum transfer is on molecular
scale
only. (c) L2T (d) L2 . T–2 (c) shear stress is caused more effectively by
cohesion than momentum transfer.
ANSWERS
1. (a) 2. (c) 3. (a) 4. (c) 5. (a) 6. (b) 7. (b) 8. (b)
9. (d) 10. (a) 11. (c) 12. (b) 13. (c) 14. (d)
(d) shear stresses are generally larger than in a similar laminar flow.
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15. Turbulent flow generally occurs for cases in- volving.
(a) highly viscous fluid
(b) very narrow passages
(c) very slow motion
(d) none of these
16. An ideal fluid is
(a) frictionless & incompressible.
, (b) one, which obeys Newton’s law of viscosity. (c) highly viscous.
(d) none of these.
17. Steady flow occurs, when the
(a) conditions change steadily with time. (b) conditions are the same
at the
adjacent
points at any instant.
(c) conditions do not change with time at any
point.
(d) rate of the velocity change is constant. 18. Which of the following
must be
followed by the flow of a fluid (real or ideal) ?
(i) Newton’s law of viscosity.
(ii) Newton’s second law of motion.
(iii) the continuity equation.
(iv) Velocity of boundary layer must be zero
relative to boundary.
(v) Fluid cannot penetrate a boundary.
(a) I, II, III (b) II, III, V
(c) I, II, V (d) II, II, V
19. The unit of velocity head is
(a) m-Kg/Sec (b) m-Kg/m3 (c) m-Kgs/Kg (d) m-Kgs/Sec
20. Bernoulli’s equation describes the
(a) mechanical energy balance in potential flow. (b) kinetic energy
balance in
1. A fluid is the one, which 8.
(a) cannot remain at rest under the action of shear force.
(b) continuously expands till it fills any con- tainer.
(c) is incompressible.
(d) permanently resists distortion.
2. In an incompressible fluid, the density is 9.
(a) greatly affected by moderate changes in pressure.
(b) greatly affected only by moderate changes in temperature.
(c) not affected with moderate change in temWith increase in the
temperature,
viscosity of 1a liquid
(a) increases
(b) decreases
(c) remains constant
(d) may increase or decrease; depends on the
liquid
For water, when the pressure increases, the viscosity
(a) also increases
(b) decreases
(c) remains constant
(d) first decreases, and then increases
perature & pressure. 10. For a fluid rotating at constant angular veloc-(d)
sensible to
changes in both temperature & ity about vertical axis as a rigid body, the prespressure. sure
intensity varies
as the
,3. Potential flow is characterized by the (a) (a) irrotational and
frictionless flow.
(b) (b) irrotational and frictional flow. (c) (c) one in which dissipation
of
mechanical en(d)
ergy into heat occurs. 11. The centre of pressure is(d) formation of eddies within
the stream.
(a)
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4. Newton’s law of viscosity relates the (b)
always below the centroid of the area. always above the centroid of
the area.
(a) shear stress and velocity. (c) a point on the line of action of the
resul(b)
velocity gradient and pressure intensity. tant force.
(c) shear stress and rate of angular deforma(d) at the centroid of the
submerged
area.
tion in a fluid. 12. A stream tube is that, which has.....cross-sec(d) pressure
gradient and rate
of angular detion entirely bounded by stream lines.formation. (a) a circular (b) any
convenient
5. Dimension of absolute viscosity is (c) a small (d) a large
(a) ML–1T–1 (b) MLT–1 Mass velocity is independent of temperature & (c)
ML–1T (d)
MLT 13.
square of the radial distance. radial distance linearly.
inverse of the radial distance. elevation along vertical direction.
,6.
pressure, when the flow is Poise is converted into stoke by (a)
(a) multiplying with density (gm/c.c.). (b)
(b) dividing by density (gm/c.c.).
(c) Multiplying with specific gravity. (c)
unsteady through unchanged cross-section. steady through changing
unchanged
crosssection. steady and the cross-section is changed.
(d) dividing by specific gravity.14. In turbulent flow, the
7. Dimension of kinematic viscosity. (a) fluid particles move in an
orderly
manner. (a) MLT–1 (b) L2 . T–1 (b) momentum transfer is on molecular
scale
only. (c) L2T (d) L2 . T–2 (c) shear stress is caused more effectively by
cohesion than momentum transfer.
ANSWERS
1. (a) 2. (c) 3. (a) 4. (c) 5. (a) 6. (b) 7. (b) 8. (b)
9. (d) 10. (a) 11. (c) 12. (b) 13. (c) 14. (d)
(d) shear stresses are generally larger than in a similar laminar flow.
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15. Turbulent flow generally occurs for cases in- volving.
(a) highly viscous fluid
(b) very narrow passages
(c) very slow motion
(d) none of these
16. An ideal fluid is
(a) frictionless & incompressible.
, (b) one, which obeys Newton’s law of viscosity. (c) highly viscous.
(d) none of these.
17. Steady flow occurs, when the
(a) conditions change steadily with time. (b) conditions are the same
at the
adjacent
points at any instant.
(c) conditions do not change with time at any
point.
(d) rate of the velocity change is constant. 18. Which of the following
must be
followed by the flow of a fluid (real or ideal) ?
(i) Newton’s law of viscosity.
(ii) Newton’s second law of motion.
(iii) the continuity equation.
(iv) Velocity of boundary layer must be zero
relative to boundary.
(v) Fluid cannot penetrate a boundary.
(a) I, II, III (b) II, III, V
(c) I, II, V (d) II, II, V
19. The unit of velocity head is
(a) m-Kg/Sec (b) m-Kg/m3 (c) m-Kgs/Kg (d) m-Kgs/Sec
20. Bernoulli’s equation describes the
(a) mechanical energy balance in potential flow. (b) kinetic energy
balance in
