A liquid of density ρρ flows through a bent tube of cross-section A,A, with a speed v.v. The liquid enters at point AA and exits at BB in the opposite direction. The radius of the bend is R.R. The tube lies on a horizontal table. The force required to hold the tube equals:

1. ρAv2ρAv2
2. 2ρAv22ρAv2
3. 2ρAv22ρAv2
4. ρv2πR2ρv2πR2

Subtopic:  Pressure |
 58%
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The bob (mass : mm) of a simple pendulum is suspended from a long wire of length L.L. When this bob is submerged in a fluid of density ρ,ρ, it is observed by means of a careful measurement that the extension in the wire is halved. The volume of bob is:
1. mρmρ 2. 2mρ2mρ
3. m2ρm2ρ 4. 3m2ρ3m2ρ
Subtopic:  Archimedes' Principle |
 62%
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A tank of uniform cross-section is filled with water. The pressure at the bottom of the tank is P0,P0, and the volume of water is V0.V0. Ignore atmospheric pressure. The potential energy of the water in the tank (taking the base as the reference) is:
1. P0V0P0V0 2. 2P0V02P0V0
3. P0V02P0V02 4. P0V04P0V04
Subtopic:  Pressure |
 51%
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Water is under high pressure within a tank. When a hole is made at the top of the tank, a stream of water rises up vertically to a height HH above the hole. Assume the flow to be streamlined. The water pressure (gauge pressure) at the top of the tank,  initially, was: (ρρ density of water)
1. HρgHρg 2. Hρg2Hρg2
3. 2Hρg2Hρg 4. 2Hρg2Hρg
Subtopic:  Bernoulli's Theorem |
 62%
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A pair of soap bubbles cling together to form a double-bubble as shown: their respective radii are 3R,R.3R,R. The radius of their interface (PQ)(PQ) is:
1. 2R2R 2. 5R
3. 3R4 4. 3R2
Subtopic:  Surface Tension |
 58%
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The surface tension of soapy water is S. When bubbles are blown with soapy water, one bubble of radius r is formed within another of radius 3r. The excess pressure within the smaller bubble, relative to the atmospheric pressure is:
1. 4Sr 2. 8S3r
3. 8Sr 4. 16S3r
Subtopic:  Surface Tension |
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Consider a tank full of water with an outlet at the bottom. As the outlet valve is opened, and water flows out, the pressure inside the tank near the outlet:
 
1. increases.
2. decreases.
3. remains unchanged.
4. increases and then quickly returns to normal.
Subtopic:  Pressure |
 58%
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Water flows from a small hole at the bottom of a rectangular tank at 10 m/s after it had been filled for 20 min. For how much time should the empty tank be filled at the same rate so that the speed of efflux is doubled? (i.e. it becomes 20 m/s)
1. 40 min
2. 80 min
3. 160 min
4. 320 min
Subtopic:  Bernoulli's Theorem |
 54%
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A viscous liquid is flowing through a straight tube under the action of a pressure difference across the ends of the tube. The tube is aligned with the x-axis. The force exerted on the tube by the liquid has the form:
(a,b>0)
1. aˆi 2. aˆi
3. aˆi+bˆj 4. aˆi+bˆj
Subtopic:  Viscosity |
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A large vessel of liquid of density ρ is contained in a tank. The tank is pulled towards the right with a constant acceleration a. The upper level of the liquid is not shown in the diagram. Then, the pressures at A and B are related by:

1. PA=PB
2. PAPB=Lρa
3. PBPA=Lρa
4. PAPB=Lρa2+g2
Subtopic:  Pressure |
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