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#fluid speed

6 public questions tagged with this topic.

Surface Tension, Capillarity and Excess Pressure

Why does the pressure in a fluid decrease when its speed increases in a horizontal pipe?

Bernoulli’s principle states that in steady flow, an increase in kinetic energy (12ρv2) corresponds to a decrease in pressure energy, as total energy is conserved along a horizontal streamline. As per NCERT, applying relevant law/formula with correct units and sign convention leads to Because of energy conservation. This satisfies dimensional consistency and physical conditions given, so option B is scientifically correct.

Ref: NCBI Bookshelf, Ideal Gas Law: P1V1/T1 = P2V2/T2.

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Viscosity, Stokes' Law and Reynolds Number

Water (ρ\=1000kg/m3) flows horizontally at 3.2m/s with pressure 1.85×105Pa. If the speed increases to 5.8m/s, what is th

Bernoulli’s equation: P1+12ρv12 = P2+12ρv22. P1 = 1.85×105Pa, v1 = 3.2m/s, v2 = 5.8m/s, ρ = 1000kg/m3. P2 = 1.85×105+12×1000(10.24−33.64) = 1.85×105−11700 = 1.733×105Pa. As per NCERT, applying relevant law/formula with correct units and sign convention leads to 1.73 × 10⁵ Pa. This satisfies dimensional consistency and physical conditions given, so option B is scientifically correct.

Ref: NCBI Bookshelf, Ideal Gas Law: P1V1/T1 = P2V2/T2.

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Equation of Continuity and Flow Rate

A pipe has a cross-sectional area of 0.02m2 at one end and 0.01m2 at the other. If water flows at 2m/s through the wider

Using the equation of continuity: A1v1 = A2v2. A1 = 0.02m2, v1 = 2m/s, A2 = 0.01m2. v2 = A1v1A2 = 0.02×20.01 = 4m/s. As per NCERT, applying relevant law/formula with correct units and sign convention leads to 4 m/s. This satisfies dimensional consistency and physical conditions given, so option C is scientifically correct.

Ref: NCERT Class 11 Physics, Thermal Properties and Gravitation.

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Fluid Pressure, Pascal's Law and Manometers

A pipe’s cross-sectional area changes from 0.08m2 to 0.02m2. If the speed at the larger end is 1.2m/s, what is the speed

Continuity equation: A1v1 = A2v2. A1 = 0.08m2, v1 = 1.2m/s, A2 = 0.02m2. v2 = A1v1A2 = 0.08×1.20.02 = 4.8m/s. As per NCERT, applying relevant law/formula with correct units and sign convention leads to 4.8 m/s. This satisfies dimensional consistency and physical conditions given, so option C is scientifically correct.

Ref: NCERT Class 11 Physics, Thermal Properties and Gravitation.

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Surface Tension, Capillarity and Excess Pressure

A pipe narrows from 0.06m2 to 0.02m2. If water flows at 1.8m/s in the wider section, what is the speed in the narrower s

Continuity equation: A1v1 = A2v2. A1 = 0.06m2, v1 = 1.8m/s, A2 = 0.02m2. v2 = A1v1A2 = 0.06×1.80.02 = 5.4m/s. As per NCERT, applying relevant law/formula with correct units and sign convention leads to 5.4 m/s. This satisfies dimensional consistency and physical conditions given, so option C is scientifically correct.

Ref: NCERT Class 11 Physics, Thermal Properties and Gravitation.

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Viscosity, Stokes' Law and Reynolds Number

A pipe narrows from 0.12m2 to 0.04m2. If water flows at 1.6m/s in the wider section, what is the speed in the narrower s

Continuity equation: A1v1 = A2v2. A1 = 0.12m2, v1 = 1.6m/s, A2 = 0.04m2. v2 = A1v1A2 = 0.12×1.60.04 = 4.8m/s. As per NCERT, applying relevant law/formula with correct units and sign convention leads to 4.8 m/s. This satisfies dimensional consistency and physical conditions given, so option C is scientifically correct.

Ref: NCERT Class 11 Physics, Thermal Properties and Gravitation.

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