Mechanical properties of fluids practice · Mixed difficulty

The density of ice and water are respectively $\mathrm{gc}{\mathrm{m}^{ - 3}}$ . If m gram of ice melts , then change in its volume is

Given below are two statements: One is labelled as
Assertion (A) and the other· is labelled as Reason
(R).
Assertion (A) : Clothes containing oil or grease
stains cannot be cleaned by water wash.
Reason (R) : Because the angle of contact
between the oil/ grease and water is obtuse.
In the light of the above statements, choose the
correct answer from the option given below.

A good lubricant should have

A tank containing water has an orifice in one vertical side. It is 10 m below the surface level of water in tank. Then velocity of efflux from that small orifice is [in m/s]

If there were no gravity, which of the following will not be there for fluid?

Extra pressure inside a soap bubble of radius $r$ is proportional to

Two pieces of glass plate one upon the other with a little water in between them cannot be separated easily because of

Surface tension of a liquid is due to

An open water tank is placed on a platform of height $16 {~m}$ from ground. Height of water in tank is $12 {~m}$ from its base and it is filled completely with water. Height of a small hole, from ground which should be made on wall of container so that water strikes at maximum distance from base of platform on ground is

When two liquids of same mass but different densities are mixed together, then the density of the mixture is

A cylindrical vessel is filled with equal amounts of weight of mercury on water. The overall height of the two layers is 29.2 cm, specific gravity of mercury is 13.6. Then the pressure of the liquid at the bottom of the vessel is

A needle of length 5 cm is floating on water of surface tension $0.07\,J{m^{ - 2}}$ and is not wetted by water. Then the weight of the needle will be (take $g = 10\,m/{s^2}$)

A barometer kept in an elevator reads $76 {~cm}$ of ${Hg}$ when elevator is accelerating upwards. Possible value of pressure inside the elevator is (in ${cm}$ of ${Hg})$

A: During takeoff of an aeroplane, velocity of air above the wing is greater than velocity below the wing
R: Bernoulli's principle is based on law of conservation of energy

A beaker containing water is balance on the pan of a common balance. A solid of specific gravity 1 and mass 5 g is tied to the arm of the balance and immersed in water contained in the beaker. The scale pan with the beaker

Which of the following statement(s) is/are correct?

I. An ice ball is floating in water. Some stone pieces are embedded inside the ice. When ice will melt, level of water will fall.

II. In floating condition, stone pieces will displace more liquid compared to the condition when they sink.

Statement-1: When a soda water bottle falls freely from a height $h$, the gas bubble rises in water from the bottom.
Statement-2: Air is lighter than liquid.

The onset of turbulence in a liquid is determined by

Assertion: To empty an oil tank, two holes are made.
Reason: Oil will come out of two holes so it will be emptied faster.

A flow of liquid is streamline, if the Reynolds' number is

Two cylinders of same cross-sectional area A and length$L$ but made of two material of densitites ${\rho _1}$ and ${\rho _2}$ (in CGS units) are cemented together to form a cylinder of length$2L$. If the combination floats in water with a length $L/2$ above the surface of water and ${\rho _1} < {\rho _2}$, then

Coatings used on raincoat are waterproof because they

Terminal velocity of a small sized spherical body having radius $r$ falling vertically in a viscous medium having coefficient of viscosity $\eta$ depends on radius of body and coefficient of viscosity as

Pressure applied to an enclosed fluid is transmitted undiminished to every point of the fluid and the walls of containing vessel. This law was first formulated by:

Find pressure on swimmer at a depth of 10 m in water

The coefficient of viscosity for hot air is

A: At constant temperature, the elongation in a liquid surface does not obey Hooke's law
R: During increase in suface area, the liquid molecules initially present just below the surface will come on to the surface and this is not real elongation

If a capillary tube is tilted to $45^\circ \,\mathrm{and}\,\,60^\circ$ from the vertical then the ratio of length ${l_1}\,{l_2}$ of liquid columns in it will be

The pressure on the top surface of an aeroplane wing was $0.90 \times {10^5}\,Pa$ and at the bottom surface is $0.91 \times {10^5}\,Pa.$ If the area of each surface is $40\,{m^2},$ the net lift force on the wing is

Assertion: The size of a hydrogen balloon increases as it rises in air.
Reason: The material of the balloon can be easily stretched.