Fluid Mechanics Paper Set for practice

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Fluid Mechanics Paper Set 2

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The power absorbed (in watts) in overcoming the viscous resistance of a footstep bearing is

1 μ π³ N² R² /1800 t

2 μ π³ N² R⁴ /1800 t

3 μ π³ N² R² /3600 t

4 μ π³ N² R⁴ /3600 t

The depth of center of pressure of an immersed surface, inclined at an angle 'θ' with the liquid surface lies at a distance equal to __________ the center of gravity.

1 IG sin²θ/Ax̅ bellow

2 IG sin²θ/Ax̅ above

3 IG sinθ/Ax̅ bellow

4 IG sinθ/Ax̅ above

The tangential velocity of the water element having a free vortex is

1 directly proportional to its distance from the centre

2 inversely proportional to its distance from the centre

3 directly proportional to its (distance)2 from the centre

4 inversely proportional to its (distance)2 from the centre

According to Darcy's formula, the loss of head due to friction in the pipe is (where f = Darcy's coefficient, l = Length of pipe, v = Velocity of liquid in pipe, and d = Diameter of pipe)

1 flv²/2gd

2 flv²/gd

3 3flv²/2gd

4 4flv²/2gd

A tank of uniform cross-sectional area (A) containing liquid upto height (H₁) has an orifice of cross-sectional area (a) at its bottom. The time required to bring the liquid level from H₁ to H₂ will be

1 2A × √H₁/Cd × a × √(2g)

2 2A × √H₂/Cd × a × √(2g)

3 2A × (√H₁ - √H₂)/Cd × a × √(2g)

4 2A × (√H3/2 - √H3/2)/Cd × a × √(2g)

A hemispherical tank of radius (R) has an orifice of cross-sectional area (a) at its bottom and is full of liquid. The time required to empty the tank completely is

The imaginary line drawn in the fluid in such a way that the tangent to any point gives the direction of motion at that point, is known as

1 path line

2 stream line

3 steak line

4 potential line

A compound pipe of diameter d₁, d₂ and d₃ having lengths l₁, l₂ and l₃ is to be replaced by an equivalent pipe of uniform diameter d and of the same length (l) as that of the compound pipe. The size of the equivalent pipe is given by

1 l/d² = (l₁/d₁²) + (l₂/d₂²) + (l₃/d₃²)

2 l/d³ = (l₁/d₁³) + (l₂/d₂³) + (l₃/d₃³)

3 l/d⁴ = (l₁/d₁⁴) + (l₂/d₂⁴) + (l₃/d₃⁴)

4 l/d⁵ = (l₁/d₁⁵) + (l₂/d₂⁵) + (l₃/d₃⁵)

Reynolds number is significant in

1 Supersonics, as with projectile and jet propulsion

2 Full immersion or completely enclosed flow, as with pipes, aircraft wings, nozzles etc.

3 Simultaneous motion through two fluids where there is a surface of discontinuity, gravity forces, and wave making effect, as with ship's hulls

4 All of the above

When a body is immersed wholly or partially in a liquid, it is lifted up by a force equal to the weight of liquid displaced by the body. This statement is called

1 Pascal's law

2 Archimedes’s principle

3 Principle of flotation

4 Bernoulli's theorem

The loss of head due to viscosity for laminar flow in pipes is (where d = Diameter of pipe, l = Length of pipe, v = Velocity of the liquid in the pipe, μ = Viscosity of the liquid, and w = Specific weight of the flowing liquid)

1 4μvl/wd²

2 8μvl/wd²

3 16μvl/wd²

4 32μvl/wd²

According to Bernoulli's equation

1 Z + p/w + v²/2g = constant

2 Z + p/w - v²/2g = constant

3 Z - p/w + v²/2g = constan

4 Z - p/w - v²/2g = constant

The torque required to overcome viscous resistance of a footstep bearing is (where μ = Viscosity of the oil, N = Speed of the shaft, R = Radius of the shaft, and t = Thickness of the oil film)

1 μπ²NR/60t

2 μπ²NR²/60t

3 μπ²NR³/60t

4 μπ²NR⁴/60t

The increase in pressure at the outer edge of a drum of radius (r) completely filled up with liquid of density (ρ) and rotating at (ω) rad/s is

1 ρ ω2 r2

2 2ρ ω2 r2

3 ρ ω2 r2/2

4 ρ ω2 r2/4

When the water level on the downstream side of a weir is above the top surface of a weir, the weir is known as

1 Narrow-crested weir

2 Broad-crested weir

3 Ogee weir

4 Submerged weir

A pressure of 25 m of head of water is equal to

1 25 kN/ m²

2 245 kN/ m²

3 2500 kN/m²

4 2500 kN/m²