Terms (Fluid Mechanics and Hydraulics) Flashcards
Liquids
a. cannot be compressed
b. do not occupy definite shape
c. are not affected by change in pressure and temperature
d. none of these
b. do not occupy definite shape
Specific weight of liquids
a. remains constant at every place.
b. does not remain constant at every place.
c. varies from place to place on the earth.
d. does not vary on any other planet.
d. does not vary on any other planet.
The specific weight of water is 1000 kg/m3
a. at normal pressure of 760 mm
b. at 4 deg C temperature
c. at mean sea level
d. all of the above
d. all of the above
Specific weight of sea water is more than that of pure water because of
a. dissolved air
b. dissolved salts
c. suspended matter
d. all of the above
d. all of the above
Water belongs to
a. Newtonian fluids
b. Non-Newtonian fluids
c. Compressible Fluids
d. None of these
a. Newtonian fluids
Fluids change the volume under external pressure due to
a. plasticity
b. viscosity
c. compressibility
d. none of these
c. compressibility
Molecules of fluids get attracted due to
a. capillary rise
b. surface tension
c. adhesion
d. cohesion
c. adhesion
Falling drops of water become spheres due to
a. adhesion
b. cohesion
c. surface tension
d. capillary rise
c. surface tension
In an open tube, free surface of mercury remains
a. horizontal
b. curved upwards
c. curved downwards
d. none of these
c. curved downwards
If cohesion between the molecules of a fluid is more than adhesion between the fluid and glass, the free level of fluid in a dipped glass tube will be
a. higher than the surface of liquid
b. same as the surface of liquid
c. lower than the surface of liquid
d. none of these
c. lower than the surface of liquid
A rise or fall of liquid in a glass tube of a very small diameter when dipped is
a. directly proportional to the force per unit length of periphery
b. directly proportional to the sine of the angle of contact
c. directly proportional to the specific weight of liquid
d. inversely proportional to the diameter of the glass tube
c. directly proportional to the specific weight of liquid
Hydrostatic pressure on dam depends upon its
a. length
b. depth
c. shape
d. both (b) and (c)
d. both (b) and (c)
Barometers are used to measure
a. pressure in water channels, pipes, etc.
b. difference in pressure at two points
c. atmospheric pressure
d. very low pressure
c. atmospheric pressure
Piezometers are used to measure
a. pressure in water channels, pipes, etc.
b. difference in pressure at two points
c. atmospheric pressure
d. very low pressure
d. very low pressure
Manometers are used to measure
a. pressure in water channels, pipes, etc.
b. difference in pressure at two points
c. atmospheric pressure
d. very low pressure
a. pressure in water channels, pipes, etc.
Differential manometers are used to measure
a. pressure in water channels, pipes, etc.
b. difference in pressure at two points
c. atmospheric pressure
d. very low pressure
b. difference in pressure at two points
The pressure less than atmospheric pressure is known
a. suction pressure
b. vacuum pressure
c. negative gauge pressure
d. all of the above
d. all of the above
Atmospheric pressure varies with
a. altitude
b. temperature
c. weather conditions
d. none of these
d. none of these
Mercury is generally used in barometers because
a. its vapor pressure is practically zero
b. the height of barometer will be less
c. it is a best liquid
d. both (a) and (b)
d. both (a) and (b)
The total pressure force on a plane area is equal to the area multiplied by the intensity of pressure at its centroid if
a. area is horizontal
b. area is vertical
c. area is inclined
d. all of the above
d. all of the above
The center of pressure of a vertical plane immersed in a liquid is at
a. center of higher edge
b. center of lower edge
c. centroid of the area
d. none of these
d. none of these
On an inclined plane, center of pressure is located
a. at the centroid
b. above the centroid
c. below the centroid
d. anywhere
c. below the centroid
When a body is totally or partially immersed in a fluid, it is buoyed up by a force equal to
a. weight of the body
b. weight of the fluid displaced by the body
c. weight of the body and fluid displaced by the body
d. difference of weights of the fluid displaced and that of the body
b. weight of the fluid displaced by the body
A floating body attains stable equilibrium if its metacenter is
a. at the centroid
b. above the centroid
c. below the centroid
d. anywhere
b. above the centroid
Center of buoyancy is
a. center of the floating body
b. centroid of the fluid displaced
c. center pressure of the displaced liquid
d. none of these
b. centroid of the fluid displaced
The rise of the liquid along the walls of a revolving cylinder above the initial level
a. greater than the depression of the liquid
b. lesser than the depression of the liquid at the axis of rotation
c. the same as the depression of the liquid at the axis of rotation
d. none of these
c. the same as the depression of the liquid at the axis of rotation
When a liquid rotates at constant angular velocity about a vertical axis of a rigid body, the pressure
a. increases linearly to its radial distance
b. varies inversely as the altitude along any vertical line
c. varies as the square of the radial distance
d. decreases as the square of the radial distance
c. varies as the square of the radial distance
The imaginary line drawn such that the tangents at its all points indicate the direction of the velocity of the fluid particles at each point is called
a. path line
b. stream line
c. potential line
d. streak line
b. stream line
In fluids, steady flow occurs when
a. conditions of flow change steadily with time
b. conditions of flow do not change with time at a point
c. conditions of flow remain the same at adjacent point
d. velocity vector remains constant at a point
b. conditions of flow do not change with time at a point
Uniform flow is said to occur when
a. size and shape of the cross-section in a particular length remain constant
b. size and shape of the cross-section change along a length
c. frictional loss in the particular length of the channel will be more than the drop in its elevation
d. frictional loss in the particular length of the channel will be less than the drop in its elevation
a. size and shape of the cross-section in a particular length remain constant
If velocities of fluid particles vary from point to point in magnitude and direction, as well as from instant to instant, the flow said to be
a. turbulent flow
b. laminar flow
c. uniform flow
d. non-uniform flow
a. turbulent flow
A steady uniform flow is through
a. an expanding tube at constant rate
b. an expanding tube at increasing rate
c. a long pipe at decreasing rate
d. a long pipe at constant rate
d. a long pipe at constant rate
A non-uniform steady flow is through
a. an expanding tube at constant rate
b. an expanding tube at increasing rate
c. a long pipe at increasing rate
d. a long pipe at decreasing rate
a. an expanding tube at constant rate
The continuity equation
a. requires that Newton’s second law of motion be satisfied at every fluid
b. relates mass rate of flow along a streamline
c. expresses the relationship between work and energy
d. related the momentum per unit volume between two points on a streamline
b. relates mass rate of flow along a streamline
Equation of continuity of fluids is applicable only if
a. flow is one dimensional
b. flow is compressive
c. flow is steady
d. all of the above
d. all of the above
The flow in which each liquid particle has a definite path, and the paths of adjacent particles do not cross each other, is called
a. steady flow
b. streamline flow
c. turbulent flow
d. uniform flow
b. streamline flow
Total head of a liquid particle in motion is the sum of
a. potential head and kinetic head
b. kinetic head and pressure head
c. potential head and pressure head
d. potential head, kinetic head and pressure head
d. potential head, kinetic head and pressure head
The main assumption of Bernoulli’s equation is:
a. No external force except the gravity acts on the liquid
b. The velocity of energy liquid particle across any cross-section of a pipe is uniform
c. There is no loss of energy of the liquid while flowing
d. All of the above
d. All of the above
Reynaldo number is the ratio of initial force and
a. elasticity
b. surface tension
c. gravitational force
d. viscosity
d. viscosity
The velocity of the fluid particle at the center of the pipe section is
a. equal throughout
b. minimum
c. maximum
d. none of these
c. maximum
An independent mass of a fluid does not possesses
a. pressure energy
b. elevation energy
c. kinetic energy
d. none of these
a. pressure energy
Frictional loss of head includes the loss of energy due to
a. viscosity
b. turbulence
c. both (a) and (b)
d. none of these
d. none of these
Energy equation is usually applicable to
a. steady flow
b. laminar flow
c. turbulent flow
d. non-uniform flow
a. steady flow
The line joining the points to which the liquid rises in vertical piezometer tubes fitted at different cross-sections of a conduit, is known as
a. hydraulic gradient
b. piezometer line
c. pressure grade line
d. all of the above
d. all of the above
Hydraulic grade line
a. may be above of below the center line of conduit
b. remains parallel to the center line of conduit
c. remains below the center of conduit
d. remains above the center of conduit
a. may be above of below the center line of conduit
Pitot tube
a. velocity of flow
b. difference in pressure
c. pressure
d. none of these
a. velocity of flow
Ratio of inertia and viscous forces
a. Weber number
b. Reynaldo number
c. Euler number
d. Froude number
b. Reynaldo number
Ratio if inertial and gravitational force
a. Weber number
b. Reynaldo number
c. Euler number
d. Froude number
d. Froude number
Mach number is the ratio of inertia force to
a. surface tension
b. elasticity
c. viscosity
d. gravitational force
b. elasticity
Weber number is the ratio of inertia force to
a. gravitational force
b. elasticity
c. surface tension
d. viscosity
c. surface tension
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