Fluid Mechanics MCQ Buoyancy of a Fluid mcq mechanical je exam
Metacentric height is the distance between:
(a) Water surface and center of pressure
(b) Metacentre and center of gravity
(c) Metacentre and center of buoyancy
(d) Metacentre and water surface |
The buoyancy depends on
(a) mass of liquid displaced
(b) viscosity of the liquid
(c) pressure of the liquid displaced
(d) depth of immersion |
A piece of wood having weight 5 kg floats in
water with 60% of its volume under the liquid. The specific gravity of wood is : |
(a) 0.83 (b) 0.6
(c) 0.4 (d) 0.3
V × ρ × g = 0.6V × ρ ×g
V × ρ × g = 0.6V × 1 × g |
In case of partially immersed body in a liquid,
(a) the upward force > weight of fluid displaced
(b) the upward force < weight of fluid displaced
(c) the upward force = weight of fluid displaced
(d) None of these |
The centre of gravity of the volume of the
liquid displaced by an immersed body is
called–
(a) meta–centre
(b) centre of pressure
(c) centre of buoyancy
(d) centre of gravity |
The metacentric height of sailing ships is
(a) 0.45 m to 1.25 m
(b) 1.5 m to 3.5 m
(c) 0.25 m to 0.35 m
(d) 5 m to 7.5 m |
Metacentric height is the distance between
(a) CG of body and centre of pressure
(b) CG of body and the metacentre |
(c) CG of body and centre of buoyancy
(d) None of these |
According to principle of floatation, the weight of liquid displaced as compared to the weightof the body is
(a) more
(b) less
(c) same
(d) depending upon the shape of the body |
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? |
(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 |
The stability of a floating body depends upon
(a) its volume
(b) its weight
(c) its metacentric height
(d) the specific weight of fluid |
The body is said to be floating when (Where, W is Weight of the body and Fb = Buoyant force)
(a) W > Fb
(b) W = Fb
(c) W < Fb
(d) None of these |
A submerged body will be in stable equilibrium if the centre of gravity is
(a) below the centre of buoyancy
(b) above the centre of buoyancy
(c) coinciding with the centre of buoyancy
(d) None of these |
A piece of metal of specific gravity 7 floats in mercury of specific gravity 13.6. What fraction of its volume is under mercury? |
(a) 0.5 (b) 0.4
(c) 0.515 (d) 0.2
| 13.6 × A × x = 7 (h + x) A |
Submarines works on which of the following
principle?
(a) Bernoulli's law
(b) Pascal's law
(c) Darcy's law
(d) Archimedes law |
Drag is defined as the force component exerted on an immersed object, the component acting in direction is ........
(a) normal to flow direction
(b) parallel to flow direction
(c) at resultant angle
(d) radial to flow direction |
When a body floating in a liquid is displaced
slightly, it oscillated about ____.
(a) Centre of gravity of body
(b) Centre of pressure
(c) Centre of buoyancy
(d) Metacentre |
What does the boyoncy depend upon ?
(a) Weight of the liquid displaced
(b) Pressure with which the liquid is displaced
(c) Viscosity of the liquid
(d) Compressibilty of the liquid
Ans : (a) |
Metacentre is the point of intersection of :
(a) vertical upward force through c.g. of body and center line of body
(b) buoyant force and the centre line of body
(c) mid–point between c.g. and center of buoyancy
(d) All of these |
For a submerged curved surface, the
component of force due to static liquid is equal to _____.
(a) Weight of the liquid supported by curved
surface
(b) Force on a projection of the curved surface on a vertical plane
(c) Area of curved surface x pressure at the
centroid of the submerged area
(d) None of these |
Force of buoyance of a floating body equals -
_____.
(a) total pressure on the vertical projection of the body
(b) total pressure on the horizontal projection of the body
(c) weight of the liquid equal to the volume of the body
(d) weight of the liquid equal to the immersed volume of the body |
A block of ice floating over water in a vessel
slowly melts in it. The water level in the vessel will
(a) start rising
(b) start falling
(c) will remain constant
(d) will depend on temperature of water |
The resultant upward pressure of a fluid on a floating body is equal to the weight of fluid
displaced by the body. This definition is
according to ........
(a) Buoyancy
(b) Equilibrium of a floating body
(c) Archimedes' principle
(d) Bernoulli's therem |
A ballon lifting in air follows the .........
(a) Law of gravitation/ieg
(b) Archimedes principle
(c) Principle of buoyancy
(d) All options are correct |
A submerged body will be in stable
equilibrium if :
(a) the centre of buoyancy B is below the centre of gravity G
(b) the centre of buoyancy B coincides withG
(c) the centre of buoyancy B is above the
metacentre M
(d) the centre of buoyancy B is above Centre of gravity G |
The centre of gravity of the volume of liquid
displaced by an immersed body is called
(a) Centre of buoyancy
(b) Metacentre
(c) Centre of gravity
(d) Centroid |
A metal piece having density exactly equal to
the density of a fluid is placed in the liquid. The metal piece will :
(a) sink to the bottom
(b) float on the surface
(c) will be partly immersed
(d) will be wholly immersed |
The resultant force on a floating body will act
(a) vertically upwards through centre of buoyancy
(b) vertically downwards through centre of
buoyancy
(c) vertically upwards through meta centre
(d) vertically downwards through meta centre |
For a submerged body, if the centre of
buoyancy coincides with the centre of gravity, the equilibrium is called
(a) stable
(b) unstable
(c) neutral
(d) None of the above |
For a floating body, match the List I with List II and select the correct answer from the options given below the lists:
List-I
A. Meta-centre is above the centre of gravity
B. meta-centre is below the centre of gravity
C. Meta-centre and centre of gravity coincides
List-II
I. Stable equilibrium
II. unstable equilibrium
III. Neutral equilibrium |
(a) A-II, B-III, C-I (b) A-I, B-II, C-III
(c) A-III, B-I,C-II (d) A-III, B-II, C-I
| Find the buoyant force acting on an aluminium cube which is suspended and immersed in a jar filled with water when it is given that the side of cube is 5.0 cm. |
(a) 2.45N (b) 1.25N
(c) 4.56N (d) 7.34N
|
= V.ρ.g
= 125×10-6×103×10
= 1.25 N |
What is the Center of Buoyancy ?
(a) The point of intersection of the buoyant force and the centre line of the body
(b) Centre of gravity of the body
(c) Centroid of displaced volume of fluid
(d) Midpoint between C.G. and metacentre |
The force of buoyancy is dependent on :
(a) Mass of liquid displaced
(b) Viscosity of fluid/
(c) Surface tension of fluid
(d) Depth of immersion
If the force of buoyancy is less than the weight of the liquid displaced then the body:
(a) will float
(b) will sink down
(c) will be submerged
(d) All of above |
For a floating body to be in stable equilibrium, its metacentre should be
(a) Below the centre of gravity
(b) Below the centre of buoyancy
(c) Above the centre of buoyancy
(d) Above the centre of gravity |
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