EASY
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A piece of solid weighs 120 gm in open air, 90 gm in water and 60 gm in a liquid. The relative density of solid and that of liquid are respectively.

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Important Questions on Fluid Mechanics

EASY

Water stands upto height 'h' behind the dam as shown in the figure. The front view of the dam gate is also shown in the adjoining figure. Density of water is 'ρ' and acceleration due to gravity is 'g'. If atmospheric pressure force is also considered, the point of application of total force acting on the dam due to water above 'o' is_____

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MEDIUM

A barometer is constructed using a liquid (density =760 kg m-3). What would be the height of the liquid column, when a mercury barometer reads 76 cm?

(density of mercury =13600 kg m-3)

HARD
Consider a vessel filled with a liquid upto height H. The bottom of the vessel lies in the X-Y plane passing through the origin. The density of the liquid varies with Z-axis as ρz=ρ02-zH2. If P1 and P2 are the pressures at the bottom surface and top surface of the liquid, the magnitude of P1-P2 is :
HARD
A submarine has a window of area 30×30 cm2 on its ceiling and is at a depth of 100 m below sea level in a sea. If the pressure inside the submarine is maintained at the sea-level atmosphere pressure, then the force acting on the window is (consider density of sea water =1.03×103 kg m-3 acceleration due to gravity =10 m s-2):
MEDIUM
A U tube with both ends open to the atmosphere is partially filled with water. Oil, which is immiscible with water, is poured into one side until it stands at a distance of 10 mm above the water level on the other side. Meanwhile, the water rises by 65 mm from its original level (see diagram). The density of the oil is ____ρw=1000 kg m-3
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EASY
The pressure at the bottom of a liquid tank is not proportional to the
MEDIUM
Two thin circular discs A and B of radii 2 cm and 4 cm are in a liquid at the same depth. TA is the thrust on A and TB thrust on B. Then TA:TB=
EASY
The dimensions for pressure is
MEDIUM
There is a circular tube in a vertical plane. Two liquids which do not mix and of densities d1 and d2 are filled in the tube. Each liquid subtends 90o angle at centre. Radius joining their interface makes an angle α with vertical. Ratio d1d2  is:
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EASY
The density of kerosene is 800kg m-3. Its relative density is
MEDIUM
Consider two wires of same material having their ratio of radii to be 2:1. If these two wires are stretched by equal force, the ratio of stress produced in them is :
EASY
A tall tank filled with water has an irregular shape as shown. The wall, CD makes an angle of, 45o with the horizontal; the wall, AB is normal to the base, BC . The lengths, AB and, CD are much smaller than the height, h of water (figure not to scale).
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Let P1, P2 and P3 be the pressures exerted by the water on the wall AB, base BC, and the wall CD, respectively. The density of water is, ρ and, g is the acceleration due to gravity. Then, approximately
EASY
The pressure acting on a submarine is 3×105 Pa at a certain depth. If the depth is doubled, the percentage increase in the pressure acting on the submarine would be: (Assume that atmospheric pressure is 1×105 Pa density of water is 103 kg m-3, g=10 ms-2)
HARD
A healthy adult of height 1.7 m has an average blood pressure (BP) of 100 mm of Hg. The heart is typically at a height of 1.3 m from the foot. Take, the density of blood to be 103 kg/m3 and note that 100 mm of Hg is equivalent to 13.3kPa (kilo pascals). The ratio of BP in the foot region to that in the head region is close to
 
EASY

The liquid shown in the figure in the two arms is mercury (specific gravity 13.6) and water. If the difference of heights of the mercury column is 2 cm, the height h of the water column is

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HARD
A U-shaped tube is partially filled with an incompressible liquid of density 1.2 g cm-3. Oil which does not mix with the liquid is next poured into the left side of the U-tube until the liquid rises by, 15 cm on the right side of U-tube. If the density of the oil is 0.9 g cm-3, the oil level will stand higher than the liquid level of the right side of U-tube by
MEDIUM
A glass flask weighing 390 g, having internal volume 500cc just floats when half of it is filled with water. Specific gravity of the glass is
HARD

An open-ended U-tube of uniform cross-sectional area contains water (density 103 kg m-3 ). Initially the water level stands at 0.29 m from the bottom in each arm. Kerosene oil (a water-immiscible liquid) of density 800 kg m-3 is added to the left arm until its length is 0.1 m, as shown in the schematic figure below. The ratio h1h2 of the heights of the liquid in the two arms is

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MEDIUM

A cylindrical vessel of base radius R and height H has a narrow neck of height h and radius r at one end (see figure). The vessel is filled with water (density ρw ) and its neck is filled with immiscible oil (density ρ0). Then the pressure at;
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HARD
A nurse measures the blood pressure of a seated patient to be 190 mm of Hg