Fluid Mechanics

1. A balloon lifting in air follows the following principle

  1. law of gravitation
  2. Archimedes principle
  3. principle of buoyancy
  4. all of the above
  5. continuity equation.

Correct answer: (D)
all of the above

2. A body floats in stable equilibrium

  1. when its meatcentric height is zero
  2. when the metancentre is above e.g.
  3. when its e.g. is below it’s center of buoyancy
  4. metacentre has nothing to do with position of e.g. for determining stability
  5. none of the above.

Correct answer: (B)
when the metancentre is above e.g.

3. A bucket of water is hanging from a spring balance. An iron piece is suspended into water without touching sides of bucket from another support. The spring balance reading will

  1. increase
  2. decrease
  3. remain same
  4. increase/decrease depending on depth of immersion
  5. unpredictable.

Correct answer: (C)
remain same

4. A fluid in equilibrium can’t sustain

  1. tensile stress
  2. compressive stress
  3. shear stress
  4. bending stress
  5. all of the above.

Correct answer: (C)
shear stress

5. A fluid is said to be ideal, if it is

  1. incompressible
  2. inviscous
  3. viscous and incompressible
  4. inviscous and compressible
  5. inviscous and incompressible.

Correct answer: (E)
inviscous and incompressible.

6. A hydraulic press has a ram of 15 cm diameter and plunger of 1.5 cm. It is required to lift a weight of 1 tonne. The force required on plunger is equal to

  1. 10 kg
  2. 100 kg
  3. 1000 kg
  4. 1 kg
  5. 10,000 kg.

Correct answer: (A)
10 kg

7. A large Roynold number is indication of

  1. smooth and streamline flow
  2. laminar flow
  3. steady flow
  4. turbulent flow
  5. highly turbulent flow.

Correct answer: (E)
highly turbulent flow.

8. A liquid compressed in cylinder has a volume of 0.04 m3 at 50 kg/cm2 and a volume of 0.039 m3 at 150 kg/cm2. The bulk modulus of elasticity of liquid is

  1. 400 kg/cm2
  2. 4000 kg/cm2
  3. 40 x 105 kg/cm2
  4. 40 x 106 kg/cm2
  5. none of the above.

Correct answer: (B)
4000 kg/cm2

9. A liquid would wet the solid, if adhesion forces as compared to cohesion forces are

  1. less
  2. more
  3. equal
  4. less at low temperature and more at high temperature
  5. there is no such criterion.

Correct answer: (B)

10. A metal with specific gravity of o floating in a fluid of same specific gravity a will

  1. sink to bottom
  2. float over fluid
  3. partly immersed
  4. be fully immersed with top surface at fluid surface
  5. none of the above.

Correct answer: (D)
be fully immersed with top surface at fluid surface

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