List of top Physics Questions on Mechanical Properties of Fluids

A spherical rain drop of mass \(m\) falls vertically through air with a terminal velocity of \(0.2\ \mathrm{ms^{-1}}\). If \(27\) such identical rain drops combine to form a bigger spherical drop, then the terminal velocity of the bigger drop if it falls vertically through air is
If the fractional compression of water at the bottom of an ocean is \(1.5\times10^{-2}\), then the depth of the ocean is \[ \left( B=2.2\times10^9\,\mathrm{N\,m^{-2}}, \; g=10\,\mathrm{m\,s^{-2}} \right) \]
Two identical rain drops are falling through air each with a terminal velocity \(V\). If the two drops coalesce to form one single big drop, then the terminal velocity of the big drop is
In an open tube manometer, the volume of the gas enclosed in the bulb is \(250\,\mathrm{cm^3}\) and the difference in the heights of the liquid levels in the manometer is \(125\,\mathrm{cm}\). The density of the liquid in the manometer is \[ \left( g=10\,\mathrm{m\,s^{-2}},\; P_{\text{atm}}=100\,\mathrm{kPa} \right) \]
A spherical ball of radius r falls through a viscous liquid. If the radius is doubled, the terminal velocity becomes:
जल (प्रवाह), चित्र के अनुसार वृत्ताकार अनुप्रस्थ काट वाली क्षैतिज संकीर्णित पाइप में दाएँ से बाएँ की ओर प्रवाहित हो रहा है। \(P\) और \(Q\) के बीच जल का दाब अंतर \(15\,Nm^{-2}\) है और \(Q\) पर पाइप की अनुप्रस्थ काट क्षेत्रफल \(40\,cm^2\) तथा \(20\,cm^2\) हैं। दी गई जानकारी के आधार पर पाइप में जल के प्रवाह की दर \(cm^3s^{-1}\) में है। \([जल का घनत्व =1000\,kg\,m^{-3}]\)

If the excess pressure inside a spherical mercury drop is \(1240\,Nm^{-2}\), then the radius of the mercury drop is:
If W is the energy required to form a soap bubble of radius R, then energy required to increase radius from R to 3R is:
An air bubble is formed in a liquid of surface tension $5 \times 10^{-2}\text{ Nm}^{-1}$. The decrease in the pressure inside the air bubble when its radius increases from 0.2 mm to 0.5 mm is}
Water is flowing steadily with certain initial velocity vertically down from a tap of area of cross-section $1.8\text{ cm}^2$. At a distance 25 cm below the tap, area of cross-section of the stream of the water is $1.2\text{ cm}^2$. The mass of the water flowing from the tap in a time of 10 s is (Acceleration due to gravity $=10\text{ ms}^{-2}$)}
A steel wire of initial length 149 cm extends by 0.5 cm when a tension of 50 N is applied along its length. If an additional tension of 100 N is applied to the same wire, then the final length of the wire is
A body initially at rest at a certain height from the ground is falling freely under gravity. At a time of one second, the body is at a height of 120 m from the ground. At a time $t=4.5\,s$, if the potential energy of the body is K times its total energy, then the value of K is (Acceleration due to gravity $=10\,ms^{-2}$)
Water flows through a horizontal pipe AB of non-uniform cross section. Water enters at A of area \(4cm^2\) with pressure \(10^5Nm^{-2}\) and velocity \(20ms^{-1}\). It leaves at B of area \(8cm^2\). The pressure at B is
For a particle executing simple harmonic motion, if the velocities at distances \(6\text{ cm}\) and \(8\text{ cm}\) from mean position are \(16\pi\text{ cms}^{-1}\) and \(12\pi\text{ cms}^{-1}\) respectively, then maximum acceleration is
A hydraulic lift has pistons of areas \(2\text{ cm}^2\) and \(50\text{ cm}^2\). To lift a car placed on the larger piston by a distance of \(150\text{ cm}\), if the work to be done by the smaller piston is \(18\text{ kJ}\), then the force to be applied on the smaller piston is:
A metal sphere of density \(9300\text{ kg m}^{-3}\) and radius \(1.5\text{ mm}\) is falling with a terminal velocity \(V\) through a vertical column of liquid of density \(1300\text{ kg m}^{-3}\) and coefficient of viscosity \(\eta\). The terminal velocity of another sphere of the same metal but of radius \(3\text{ mm}\) falling through another liquid of density \(800\text{ kg m}^{-3}\) and coefficient of viscosity \(1.7\eta\) is:
Two metal wires A and B of lengths 80 cm and 120 cm respectively having equal cross-sectional area are connected to form a long wire. When the combination is subjected to a tension, the elongations of the wires A and B are 0.8 mm and 1.5 mm respectively. If the Young's modulus of the material of wire A is \(1.6\times10^{11}\text{ Nm}^{-2}\), then the Young's modulus of the material of wire B (in \(10^{11}\text{ Nm}^{-2}\)) is:
A body of mass \(4\,kg\) moving with a velocity of \(12\,ms^{-1}\) collides head-on with a stationary body of mass \(2\,kg\). If the relative velocity of separation of the two bodies after collision is \(6\,ms^{-1}\), then the percentage loss of kinetic energy of the body of mass \(4\,kg\) is:
If the average terminal velocity of rain drop is 2 ms\(^{-1}\), then the energy transferred by rain to each square meter of the surface at a place which receives 100 cm of rain in a year is
The flow of oil of density $800\text{ kgm}^{-3}$ through a horizontal pipe is streamlined. If the pressure between two points separated by 1m in the tube falls by $1.6\text{ Nm}^{-2}$, then the change in kinetic energy per kg of the liquid between these points is
Name the instrument used to measure the specific gravity (relative density) of a liquid.
A horizontal pipeline carries water in streamline flow. At $A_1 = 10$ cm$^2$, $v_1 = 1$ m/s and $P_1 = 2000$ Pa. The pressure at $A_2 = 5$ cm$^2$ is \dots [$\rho = 1000$ kg/m$^3$]
The maximum length of water column that can stay without falling in a vertically held capillary tube of diameter 1mm and open at both the ends is (Acceleration due to gravity = 10 ms$^{-2}$ and surface tension of water = 0.07 Nm$^{-1}$)
A rain drop of diameter 1 mm falls with a terminal velocity of 0.7 ms$^{-1}$ in air. If the coefficient of viscosity of air is $2\times10^{-5}$ Pas, the viscous force on the rain drop is
The pressure inside a mercury drop of diameter 2 mm is (Surface tension of mercury $= 0.5 Nm^{-1}$ and atmospheric pressure $= 10^5$ Pa)