Fluid Mechanics - Mechanics - Physics Previous Year Questions

For which of the following Reynold's number, a flow is streamlined?

Water is filled in a tank up to a height of 20 cm from the bottom of the tank. Water flows through a hole of area $1 \mathrm{~mm}^2$ at its bottom. The mass of the water coming out from the hole in a time of 0.6 s is

If the terminal velocity of a metal sphere of mass 8 g falling through a liquid is $3 \mathrm{cms}^{-1}$, then the terminal velocity of another sphere of mass 64 g made of the same metal falling through same liquid is

The work done in blowing a soap bubble of diameter 3 cm is (surface tension of soap solution $=0.035 \mathrm{Nm}^{-1}$ )

A rain drop of diameter 1 mm falls with a terminal velocity of $0.7 \mathrm{~ms}^{-1}$ in air. If the coefficient of viscosity of air is $2 \times 10^{-5} \mathrm{~Pa}$-s, the viscous force on the rain drop is

Due to the presence of air resistance, if a body dropped from a height of 20 m reaches the ground with a speed of $18 \mathrm{~ms}^{-1}$, then the time taken by the body to reach the ground is nearly

A thin film of water is formed between two straight parallel wires each of length 8 cm separated by distance of 0.6 cm . The work done to increase the distance between the wires to 0.8 cm is (Surface tension of water $=0.07 \mathrm{Nm}^{-1}$ )

An air bubble rises from the bottom to the top of a water tank in which the temperature of the water is uniform. The surface area of the bubble at the top of the tank is $125 \%$ more than its surface area at the bottom of the tank. If the atmospheric pressure is equal to the pressure of 10 m water column, then the depth of water in the tank is

If $W_1$ is the work done in increasing the radius of a soap bubble from ' $r$ ' to ' $2 r$ ' and $W_2$ is the work done in increasing the radius of the soap bubble from ' $2 r$ ' to ' $3 r$ ', then $W_1: W_2=$

A cube of side 40 cm is floating with $\frac{1}{4}$ th of its volume immersed in water. When a circular disc is placed on the cube, it floats with $\frac{2}{5}$ th of its volume immersed in water. The mass of the disc is

The maximum length of water column that can stay without falling in a vertically held capillary tube of diameter 1 mm and open at both the ends is (Acceleration due to gravity $=10 \mathrm{~ms}^{-2}$ and surface tension of water $=0.07 \mathrm{Nm}^{-1}$ )

A wooden block of outer volume 1 litre and specific gravity $\frac{3}{4}$ having a cavity floats with half of its volume immersed in water. Then, the volume of the cavity is