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Mechanical Engineering :: Hydraulics and Fluid Mechanics in ME

  1. Mach number is significant in

  2. A.

     Supersonics, as with projectiles and jet propulsion

    B.

     Full immersion or completely enclosed flow, as with pipes, aircraft wings, nozzles etc.

    C.

     Simultaneous motion through two fluids where there is a surface of discontinuity, gravity force, and wave making effects, as with ship's hulls

    D.

     All of the above


  3. A piece of metal of specific gravity 13.6 is placed in mercury of specific gravity 13.6, what fraction of it volume is under mercury?

  4. A.

     The metal piece will simply float over the mercury

    B.

     The metal piece will be immersed in mercury by half

    C.

     Whole of the metal piece will be immersed with its top surface just at mercury level

    D.

     Metal piece will sink to the bottom


  5. A piece of metal of specific gravity 7 floats in mercury of specific gravity 13.6. What fraction of its volume is under mercury?

  6. A.

     0.5

    B.

     0.4

    C.

     0.515

    D.

     0.5


  7. The power transmitted through a pipe is (where w = Specific weight in N/m3, and Q = Discharge in m3/s)

  8. A.

     w × Q × H

    B.

     w × Q × hf

    C.

     w × Q (H - hf)

    D.

     w × Q (H + hf)


  9. In a single casing, multistage pump running at constant speed, the capacity rating is to be slightly lowered. It can be done by

  10. A.

     Designing new impeller

    B.

     Trimming the impeller size to the required size by machining

    C.

     Not possible

    D.

     Some other alterations in the impeller


  11. An air vessel is provided at the summit in a siphon to

  12. A.

     Avoid interruption in the flow

    B.

     Increase discharge

    C.

     Increase velocity

    D.

     Maintain pressure difference


  13. In a free vortex motion, the radial component of velocity everywhere is

  14. A.

     Maximum

    B.

     Minimum

    C.

     Zero

    D.

     Nonzero and finite


  15. The celerity (velocity) of a pressure wave in a fluid is given by (where K = Bulk modulus, and ρ = Density of the fluid)

  16. A.

     K.ρ

    B.

     K/ρ

    C.

     ρ/K

    D.

     None of these


  17. When a cylindrical vessel containing liquid is revolved about its vertical axis at a constant angular velocity, the pressure

  18. A.

     Varies as the square of the radial distance

    B.

     Increases linearly as its radial distance

    C.

     Increases as the square of the radial distance

    D.

     Decreases as the square of the radial distance


  19. A fluid in equilibrium can't sustain

  20. A.

     Tensile stress

    B.

     Compressive stress

    C.

     Shear stress

    D.

     Bending stress