EASY

Earn 100

"In a closed room dust generally settles down". Why ?

Important Questions on Mechanical Properties of Fluids

MEDIUM

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A barometer is constructed using a liquid (density $= 760 kg m^{- 3}$ ). What would be the height of the liquid column, when a mercury barometer reads $76 cm ?$

(density of mercury $= 13600 kg m^{- 3}$ )

EASY

Physics>Mechanical Properties of Matter>Mechanical Properties of Fluids>Mechanical Properties of Fluids

In Guericke's experiment to show the effect of atmospheric pressure, two copper hemispheres were tightly fitted to each other to form a hollow sphere and the air from the sphere was pumped out to create vacuum inside. If the radius of each hemisphere is

R

and the atmospheric pressure is

P

, then the minimum force required (when the two hemispheres are pulled apart by the same force) to separate the hemispheres is

MEDIUM

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A cylindrical vessel of base radius $R$ and height $H$ has a narrow neck of height $h$ and radius $r$ at one end (see figure). The vessel is filled with water (density $ρ_{w}$ ) and its neck is filled with immiscible oil (density $ρ_{0}$ ). Then the pressure at;
Question Image

MEDIUM

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Two thin circular discs

A

and

B

of radii

2 cm

and

4 cm

are in a liquid at the same depth.

T_{A}

is the thrust on

A

and

T_{B}

thrust on

B

. Then

T_{A} : T_{B} =

HARD

Physics>Mechanical Properties of Matter>Mechanical Properties of Fluids>Mechanical Properties of Fluids

Two spheres

P

and

Q

of equal radii have densities

ρ_{1}

and

ρ_{2}

, respectively. The spheres are connected by a massless string and placed in liquids

L_{1}

and

L_{2}

of densities

σ_{1}

and

σ_{2}

and viscosities

η_{1}

and

η_{2}

, respectively. They float in equilibrium with the sphere

P

L_{1}

and sphere

Q

L_{2}

and the string being taut (see figure). If sphere

P

alone in

L_{2}

has terminal velocity

{\vec{V}}_{P}

and

Q

alone in

L_{1}

has terminal velocity

{\vec{V}}_{Q}

, then

EASY

Physics>Mechanical Properties of Matter>Mechanical Properties of Fluids>Mechanical Properties of Fluids

The velocity of water in river is

18 k m h^{- 1}

near the surface. If the river is

5 m

deep, then the shearing stress between the surface layer and the bottom layer is (coefficient of viscosity of water,

η = 10^{- 3} P a s

)

MEDIUM

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A piece of copper having a rectangular cross-section of

15.2 mm x 19.1 mm

is pulled in tension with

44, 500 N

force, producing only elastic deformation. Calculate the resulting strain? Shear modulus of elasticity of copper is

42 x 10^{9} N m^{- 2}

EASY

Physics>Mechanical Properties of Matter>Mechanical Properties of Fluids>Mechanical Properties of Fluids

Describe the effect of nature of liquid and temperature on surface tension?

EASY

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Explain with an example how shear stress is cause due to tangential force.

HARD

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A uniform solid cylinder of length

l

submerged partially in two immiscible liquids is in equilibrium as shown. If one-third length of the cylinder is submerged in liquid of density

4 ρ_{0}

HARD

Physics>Mechanical Properties of Matter>Mechanical Properties of Fluids>Mechanical Properties of Fluids

What do you mean by shear stress?

MEDIUM

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Which kind of force is cause of shear stress?

MEDIUM

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How shear stress for fluids is different from solids?

EASY

Physics>Mechanical Properties of Matter>Mechanical Properties of Fluids>Mechanical Properties of Fluids

The Young's modulus of a perfectly rigid body is

EASY

Physics>Mechanical Properties of Matter>Mechanical Properties of Fluids>Mechanical Properties of Fluids

The _____ of a fluid is defined as the ratio of the shearing stress between adjacent layers of fluid to the rate of change of velocity perpendicular to the direction of motion.

EASY

Physics>Mechanical Properties of Matter>Mechanical Properties of Fluids>Mechanical Properties of Fluids

In Millikan's experiment, an oil drop of radius