Mechanical properties of fluids practice · Mixed difficulty

Assertion: If an object is submerged in fluid at rest, the fluid exerts a force on its surface.
Reason: Force exerted by the fluid at rest has to be parallel to the surface in contact with it.

An air-tight cage with a parrot sitting in it is suspended from the spring balance. The parrot starts flying. The reading of the spring balance will

The area of cross-section of a large tank is $0.5 \mathrm{~m}^2$. It has an opening near the bottom having area of cross-section $1 \mathrm{~cm}^2$. A load of $20 \mathrm{~kg}$ is applied on the water at the top. Find the velocity of the water coming out of the opening at the time when the height of water level is $50 \mathrm{~cm}$ above the bottom. (approx.) (Take $g=10 \mathrm{~m} / \mathrm{s}^2$)

Given below are two statements:

Statement-I: When a capillary tube is dipped into a liquid, the liquid neither rises nor falls in the capillary. The contact angle may be $0^{\circ}.$

Statement-II: The contact angle between a solid and a liquid is a property of the material of the solid and liquid as well.

In the light of above statement, choose the correct answer from the options given below.

Assertion: When height of a tube is less than liquid rise in the capillary tube, the liquid does not overflow.
Reason: Product of radius of meniscus and height of liquid in capillary tube always remains constant.

A water tank standing on the floor has two small holes punched in the vertical wall one above the other. The holes are $2.4 \mathrm{~cm}$ and $7.6 \mathrm{~cm}$ above the floor. If the jet of water from the holes hit the floor at the same point, then the height of water in the tank is

A tank is filled to a height $H$. The range of water coming out of a hole which is a depth $H / 4$ from the surface of water level is

A waterproofing agent changes the angle of contact

A body weighs $160g$ in air, $130g$ in water and in oil. The specific gravity of oil is

A small sphere is falling in a viscous liquid with terminal speed. The work done by viscous force on the body in taking it through a finite displacement is;

A solid sphere of radius $R$ acquires a terminal velocity ${v_1}$ when falling (due to gravity) through a viscous fluid having a coefficient of viscosity $\eta$. The sphere is broken into 27 identical solid spheres. If each of these spheres acquires a terminal velocity, ${v_2}$ when falling through the same fluid, the ratio $\left( {{v_1}/{v_2}} \right)$ equals

If Reynold's number is greater than 3000, the flow of liquid is:

The water flows from a tap of diameter $1.25cm$ with a rate of $5 \times {10^{ - 5}}{m^3}{s^{ - 1}}$. The density and coefficient of viscosity of water are ${10^3}kg{m^{ - 3}}$ and ${10^{ - 3}}$ Pas, respectively. The flow of water is

What is the maximum height (in $\mathrm{m}$ ) of a brick column of uniform cross section for which column deformation due to its own weight is within the elastic limit? $\left[\mathrm{P}_{\text {atmospheric }}=100 \mathrm{kPa}, \rho=1.8 \times 10^3\right.$ $\mathrm{kg} / \mathrm{m}^3$. Elastic limit, $\sigma=3.7 \mathrm{MPa}$.]

The work done in blowing a soap bubble of radius 0.2 m is (Surface tension of water is 0.06 N/m )

Two stretched membranes of area$2\mathrm{c}{\mathrm{m}^2}$ and$3\mathrm{c}{\mathrm{m}^2}$ are placed in a liquid at the same depth. The ratio of pressure on them is

A straw $6\,cm$ long floats on water. The water film on one side has surface tension of $50\,dyne/cm$ on the other side camphor reduces the surface tension to $40\,dyne/cm$.The force is

Sudden fall of pressure at a place indicates:

An object is located at 2 km beneath the surface of the water. If the fractional compression $\frac{{\Delta V}}{V}$ is 1.36%, the ratio of hydraulic stress to the corresponding hydraulic strain will be………
(Take, density of water is $1000\,\mathrm{ }kg\mathrm{ }\,{m^{ - 3}}$ and $g = 9.81\,\mathrm{ m}\,{\mathrm{s}^{ - 2}}$ )

A tube of length $3 \mathrm{~m}$ is filled completely with an incompressible liquid of mass $2 \mathrm{~kg}$ and closed at both ends. The tube is rotated in horizontal plane about one of its ends with angular speed of $1 \mathrm{~rad} / \mathrm{s}$. The force exerted by liquid at other end is

With an increase in temperature, surface tension of liquid (except molten copper and cadmium)

Assertion: The contact angle between water and glass is acute.
Reason: The surface of water in the capillary is convex.

A square frame of side $L$ is dipped in a liquid. On taking out, a membrane is formed. If the surface tension of the liquid is $T$, the force acting on one side of the frame will be

A soap bubble of diameter $a$ is produced using the soap solution of surface tension $T$. Find the energy required to double the radius of the bubble without change of temperature.

In a streamline flow if the gravitational head is $h$. The kinetic and pressure heads are

Wax is coated on the inner wall of a capillary tube and the tube is then dipped in water. Then, compared to the unwaxed capillary, the angle of contact $\theta$ and the height $h$ upto which water rises change. These changes are :

Eight identical drops of water, each of radius $2 \mathrm{~mm}$ are falling through air at a terminal velocity of $8 \mathrm{~cm} \mathrm{~s}^{-1}.$ If they coalesce to form a single drop, then the terminal velocity of combined drop will be:

An air foil has:

A water drop is divided into eight equal droplets. The pressure difference between the inner and outer side of the big drop will be

A drop of radius $R$ is split under isothermal conditions into $n$ droplets, each of radius $r$ the ratio of surface energies of big and each small drop is