Fluid Mechanics - Study Mode

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[#181] When the water is warm, the height to which it can be lifted by a pump

(A) Decreases due to reduced viscosity

(B) Decreases due to reduced vapour pressure

(C) Increases due to increased vapour pressure

(D) Decreases due to increased frictional resistance

Correct Answer

(B) Decreases due to reduced vapour pressure

[#182] For a particle settling in water at its terminal settling velocity, which of the following is true?

(A) Buoyancy = weight + drag

(B) Weight = buoyancy + drag

(C) Drag = buoyancy + weight

(D) Drag = weight

Correct Answer

(B) Weight = buoyancy + drag

[#183] Pick out the wrong statement.

Correct Answer

(C) An ideal fluid is the one, which has negligible surface tension and obeys the Newton's law of viscosity
(G) In case of unsteady fluid flow, the velocity at any given point does not change with time
(J) The eddy viscosity is a fluid property
(P) With increase in the Mach number > 0.6, the drag co-efficient decreases in case of compressible fluids
(T) Both B and C
(U) In a static mass of liquid, the pressure at a point is the same for all liquids
(Z) Newton's law of viscosity is not applicable to the turbulent flow of fluid with linear velocity distribution

[#184] Consider two pipes of same length and diameter through which water is passed at the same velocity. The friction factor for rough pipe is f 1 and that for smooth pipe is f 2 . Pick out the correct statement.

(A) f 1 = f 2

(B) f 1 < f 2

(C) f 1 > f 2

(D) Data not sufficient to relate f 1 & f 2

Correct Answer

[#185] Boundary layer exists in flow

(A) Of real fluids

(B) Over flat surfaces only

(C) In pipes only

(D) Of ideal fluids only

Correct Answer

(A) Of real fluids