Mechanical Engineering - Fluid Mechanics - Basic Concept of Fluid Mechanics

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Question - 1

The depth of a fluid is measured in vertical Z-direction; X and Yare the other two directions and are mutually perpendicular. The static pressure variation in the fluid is given by (symbols have the usual meanings)

  • A \(\frac{dp}{dz}=g\)
  • B \(\frac{dp}{dz}=\rho\)
  • C \(\frac{dp}{dz}=\rho g\)
  • D \(\frac{dp}{dz}=-\rho g\)

Question - 2

The expression \((p+\rho gz+\frac{\rho V^{2}}{2})\) commonly used to express Bernoulli's equation, has units of total energy
per unit

  • A mass
  • B weight
  • C volume
  • D cross-sectional area of flow

Question - 3

A differential manometer as shown in figure below is used to measure the difference in pressure at points A and B in terms of specific weight of water w. The specific gravities of the liquids x, y and z are respectively, S1,S2 and S3·

The correct difference \((\frac{P_{A}}{W}-\frac{P_{a}}{W})\) is given by

  • A h3S2 - h1S1 + h2S3
  • B h1,S1 + h2S3 - h3S2
  • C h3S1 - h1S2 + h2S3
  • D h1S1 + h2S2 - h3S3

Question - 4

The normal stress is the same in all directions at a point in a fluid only when

  • A the fluid is frictional
  • B the fluid is frictionless and incompressible
  • C the fluid has zero viscosity and is at rest
  • D one fluid layer has not motion relative to an adjacent layer

Question - 5

The shear stress developed in a lubricating oil, of viscosity 9.81 poise, filled between two parallel plates 1 cm apart and moving with relative velocity of 2 m/s is

  • A 20 N/m2
  • B 19.62 N/m2
  • C 29.62 N/m2
  • D 40 N/m2

Question - 6

An oil of specific gravity 0.9 has viscosity of 0.28 stokes at 380C. What will be its viscosity in N-s/m2?

  • A 0.2520
  • B 0.0311
  • C 0.0252
  • D 0.0206

Question - 7

A wooden rectangular block of length L is made to float in water with its axis vertical. The centre of gravity of the floating body is 0.15 L above the centre of buoyancy. What is the specific gravity of the wooden block?

  • A 0.6
  • B 0.65
  • C 0.7
  • D 0.75

Question - 8

What are the dimensions of kinematic viscosity of a fluid?

  • A [LT-2]
  • B [L2T-1]
  • C [ML -1T-1]
  • D [ML-2T-2]

Question - 9

Resultant pressure of the liquid in case of an immersed body acts through which one of the following?

  • A Centre of gravity
  • B Centre of pressure
  • C Metacentre
  • D Centre of buoyancy

Question - 10

What is buoyant force?

  • A Lateral force acting on a submerged body
  • B Resultant force acting on a submerged body
  • C Resultant force due to water on a body
  • D Resultant hydrostatic force on a body due to fluid surrounding it
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