Mechanical properties of fluids practice · Mixed difficulty

$16c{m^3}$Of water flows per sec through a capillary tube of radius a cm and of length $l$ cm when connected to a pressure head of $h$ cm of water. If a tube of the same length and radius $a/2$ cm is connected to the same pressure head, the quantity of water flowing through the tube per second will be

Bernoulli’s principle applies to streamline flow for which Reynold’s number:

An object is floating in a liquid, kept in a container. The container is placed in a lift. Choose the correct option.

A box filled with water has a small hole on its side near the bottom. It is dropped from the top of a tower. As it falls, a camera attached on the side of the box records the shape of the water stream coming out of the hole. The resulting video will show

A block of wood floats in water with (4/5) th of its volume submerged. If the same block just floats in a liquid, the density of the liquid is (in $\mathrm{kgm}^{-3}$ )

Statement A: A piece of ice floats in water. The level of water remains unchanged when the ice melts completely.
Statement B: According to Archimedes' principle, the loss in weight of the body in the liquid is equal to the weight of the liquid displaced by the immersed part of the body.

Six identical small liquid drops are mixed together to form a bigger drop. The terminal velocity of bigger drop if terminal velocity of small drop is 10 m/s, will be

The work done in blowing a soap bubble of surface tension $0.06 \mathrm{Nm}^{-1}$ from $2 \mathrm{~cm}$ radius to $5 \mathrm{~cm}$ radius is

If $F_C$ and $F_A$ denote cohesive and adhesive forces on a liquid molecule near the surface of a solid, then the surface of liquid is concave, when

A tank filled with non-viscous, incompressible, temperature-independent liquid has a hole in its bottom and water is flowing out of it. If the size of the hole is increased, then:

Statement-A: If the angle of contact is equal to $\pi / 2$ then the level of liquid in capillary is same as outside the capillary.
Statement-B: If the angle of contact is less than $\pi / 2$ then the liquid rises in the capillary.

Two mercury drop (each of radius $r)$ merge to form a bigger drop, if T is the surface tension is

A spring balance reads $w_1$ when a ball of mass $m$ is suspended from it. A weighing machine reads $w_2$ when a beaker of liquid is kept on the pan of balance. When the ball is immersed in liquid, the spring balance reads $w_3$ and the weighing machine reads $w_4$. The two balances are now so arranged that the suspended mass is inside the liquid in a beaker. Then,

A small hole is made at the bottom of a hollow sphere. The water enters into it when it is taken to a depth of 40 cm under water. If the surface tension of water is $0.07\,N{m^{ - 1}},$ diameter of the hole is

Assertion: Oil spreads on cold water.
Reason: The surface tension of oil is greater than that of cold water.

The terminal speed of a sphere of gold $\left( {\mathrm{density} = 19.5\mathrm{kg}{\mathrm{m}^{ - 3}}} \right)$ is $0.2\mathrm{m}{\mathrm{s}^{ - 1}}$ in a viscous liquid $\left( {\mathrm{density} = 1.5\mathrm{kg}{\mathrm{m}^{ - 3}}} \right)$. Then the terminal speed of a sphere of silver $\left( {\mathrm{density} = 10.5\mathrm{kg}{\mathrm{m}^{ - 3}}} \right)$ of the same size in the same liquid is

A large tank is filled with water to a height $H$. A small hole is made at the base of the tank. It takes ${T_1}$ time to decrease the height of water to $\frac{H}{\eta }\left( {\eta > 1} \right):$ and it takes ${T_2}$ time to take out the rest of water. If ${T_1} = {T_2}$, then the value of $\eta$ is

$10 \mathrm{~min}$ are taken to empty a rectangular vessel of height $h$ through an orifice in its bottom. How much time will it take to be emptied the vessel when half filled?

Dimensions of coefficient of viscosity are

Why the blood pressure in humans is greater at the feet than at the brain:

An aeroplane of mass $3 \times 10^4 \mathrm{~kg}$ and total wing area $120 \mathrm{~m}^2$ is in level flight at some height. The difference in pressure between upper and lower surfaces in kilopascal is $\left(g=10 \mathrm{~m} / \mathrm{s}^2\right)$

Ice pieces are floating in beaker A containing water also in a beaker B containing miscible liquid of specific gravity 1.2. When ice melts, the level of

Bernoulli’s principle is not involved in the working/explanation of

Water rises in plant fibres due to

Assertion: A rain drop after falling through some height attains a constant velocity.
Reason: At constant velocity, the viscous drag is just equal to its weight.

A large ship can float but a steel needle sinks because of

Typical silt(hard mud) particle of radius $20\mathrm{\mu m}$ is on the top of lake water, its density is $2000\mathrm{kg}{\mathrm{m}^{ - 3}}$ and the viscosity of lake water is 1.0 mPa, density is $1000\mathrm{kg}{\mathrm{m}^{ - 3}}$. If the lake is still(has no internal fluid motion). The terminal speed with which the particle hits the bottom of the lake is ………. $\mathrm{mm}{\mathrm{s}^{ - 1}}$

When two capillary tubes of different diameters are dipped vertically, the rise of the liquid is

A piston of cross-sectional area $100 \mathrm{~cm}^2$ is used in a hydraulic pressure to exert a force of $10^7$ dyne on the water. The cross-sectional area of the other piston which supports an object having a mass of $2000 \mathrm{~kg}$ is

Why the dam of water reservoir is thick at the bottom