Mechanics of Fluids Mid - I, September - 2014

1.Newton's law of viscosity relates
  • Intensity of pressure and rate of angular deformation
  • Shear stress and rate of angular deformation
  • Shear stress, viscosity and temperature
  • Viscosity and rate of angular deformation
Answer: B
2.The position of center of pressure on a plane surface immersed vertically in a static mass of fluid is
  • at the centroid of the submerged area
  • always above the centroid of the area
  • always below the centroid of the area
  • none of the above
Answer: C
3.If the dynamic viscosity of a fluid is 0.5 poise and specific gravity is 0.5, then the kinematic viscosity of that fluid in stokes is
  • 0.25
  • 0.50
  • 1.0
  • none of the above
Answer: C
4.Metacentric height for small values of angle of heel is the distance between the
  • centre of gravity and centre of buoy-ancy
  • centre of gravity and metacentre
  • centre of buoyancy and metacentre
  • free surface and centre of buoyancy
Answer: B
5.Equation of continuity is based on the principle of conservation of
  • mass
  • energy
  • momentum
  • none of the above
Answer: A
6.An open tank contains 1 m deep water with 50 cm depth of oil of specific gravity 0.8 above it. The intensity of pressure at the bottom of tank will be
  • 4 kN/m2
  • 10 kN/m2
  • 12 kN/m2
  • 14 kN/m2
Answer: D
7.Stream lines and path lines always coincide in case of
  • steady flow
  • laminar flow
  • uniform flow
  • turbulent flow
Answer: A
8.The fluid property, due to which, mercury does not wet the glass is
  • surface tension
  • viscosity
  • cohesion
  • adhesion
Answer: A
9.A rectangular block 2 m long, 1 m wide and 1 m deep floats in water, the depth of immersion being 0.5 m. If water weighs 10 kN/m3, then the weight of the block is
  • 5kN
  • l0kN
  • 15 kN
  • 20 kN
Answer: B
10.A right circular cylinder open at the top is filled with liquid and rotated about its vertical axis at such a speed that half the liquid spills out, then the pressure intensity at the center of bottom is
  • Zero
  • one-fourth its value when cylinder was full
  • One-half its value when cylinder was full
  • cannot be predicted from the given data
Answer: A
11.The excess pressure inside a soap bubble of diameter 1 cm is _______________ . Assume the surface tension of soap solution is to be 0.04 N/m2.
Answer: 32 N/m2.
12.Stream line, Streak line and path line are all identical in case of ______________.
Answer: Steady flow
13.Pitot tube is used to measure ________________________.
Answer: Velocity
14.The difference in mercury levels in U-tube manometer is 10 cm. The pressure difference in terms of kerosene of specific gravity 0.8 is ______________________.
Answer: 16 cm
15.The flow is described by the velocity field is given by V = 5x3i - 15x2yj + tk. The acceleration at a point (1,2,3) and at t = 1 is ____________
Answer: 167.7 units
16.If the Reynolds number is less than 2000, the flow in a pipe is ______________________.
Answer: Laminar
17.If the flow is irrotational the fluid is _______________________.
Answer: Ideal fluid
18.Pascal’s law states that at a point is equal in all directions ________________________.
Answer: In a fluid at rest
19.Differential manometers are used for measuring __________________________.
Answer: Difference of pressure between two points
20.An open cubical tank of 2 m side is filled with water. If the tank is rotated with acceleration such that half of the water spills out, then the acceleration is equal to __________.
Answer: g