Fluid Mechanics — Quiz 1

Questions in this quiz (10)

1. An oil has a dynamic viscosity of $$0.0012\ \text{Pa}\cdot\text{s}$$ and a density of $$900\ \text{kg/m}^3$$. Determine the kinematic viscosity of this oil.

   • 0.90 cSt
   • 1.33 cSt
   • 0.013 cSt
   • 9.00 cSt

2. A point is located $$10\ \text{m}$$ below the surface of a freshwater reservoir. Assuming the density of water is $$1000\ \text{kg/m}^3$$ and $$g=9.81\ \text{m/s}^2$$, determine the gauge pressure at this point.

   • 98.1 kPa
   • 147.2 kPa
   • 196.2 kPa
   • 117.7 kPa

3. Water flows through a horizontal Venturi meter with an inlet diameter of $$250\ \text{mm}$$ and a throat diameter of $$125\ \text{mm}$$. A differential manometer indicates a head difference of $$0.6\ \text{m}$$ of water. Assuming a discharge coefficient of $$0.97$$, determine the flow rate.

   • 38.6 L/s
   • 46.2 L/s
   • 52.8 L/s
   • 61.4 L/s

4. Water flows through a pipe with an inlet velocity of $$3\ \text{m/s}$$ at a pressure of $$300\ \text{kPa}$$ and elevation of $$0\ \text{m}$$. At a downstream section, the pressure is $$220\ \text{kPa}$$ and elevation is $$4\ \text{m}$$. Assuming frictionless flow and $$\rho=1000\ \text{kg/m}^3$$, determine the velocity at the downstream section.

   • 3.8 m/s
   • 5.1 m/s
   • 6.4 m/s
   • 7.2 m/s

5. Water flows at $$12\ \text{m/s}$$ past a surface where the local absolute pressure is $$75\ \text{kPa}$$. The vapor pressure is $$2.3\ \text{kPa}$$ and $$\rho=1000\ \text{kg/m}^3$$. Determine the cavitation number.

   • 0.52
   • 0.64
   • 0.78
   • 1.05

6. Water with bulk modulus $$K=2.1\ \text{GPa}$$ and density $$\rho=1000\ \text{kg/m}^3$$ flows in a steel pipe with elastic modulus $$E=200\ \text{GPa}$$, diameter $$D=250\ \text{mm}$$, and wall thickness $$t=8\ \text{mm}$$. Determine the pressure wave speed considering pipe elasticity.

   • 1120 m/s
   • 1265 m/s
   • 1380 m/s
   • 1490 m/s

7. A Venturi meter with inlet diameter $$180\ \text{mm}$$ and throat diameter $$90\ \text{mm}$$ measures a differential head of $$0.7\ \text{m}$$ of water. The measured actual flow rate is $$28.5\ \text{L/s}$$. Assuming $$g=9.81\ \text{m/s}^2$$, determine the discharge coefficient.

   • 0.86
   • 0.92
   • 0.97
   • 1.03

8. A rectangular plate $$1.2\ \text{m}$$ wide and $$1.8\ \text{m}$$ tall is submerged vertically in water and hinged at its bottom edge. The top of the plate is $$2.5\ \text{m}$$ below the water surface. Assume $$\rho=1000\ \text{kg/m}^3$$ and $$g=9.81\ \text{m/s}^2$$. Determine the moment of hydrostatic force about the bottom hinge.

   • 68 kN·m
   • 84 kN·m
   • 96 kN·m
   • 112 kN·m

9. Water flows through an orifice with an area of $$0.006\ \text{m}^2$$. The cross-sectional area of the jet at vena contracta is $$0.0039\ \text{m}^2$$. Determine the coefficient of contraction.

   • 0.52
   • 0.65
   • 0.72
   • 1.54

10. An open tank with cross-sectional area $$8\ \text{m}^2$$ has an orifice at the bottom with area $$0.008\ \text{m}^2$$ and discharge coefficient $$0.62$$. Determine the time required to lower the water level from $$3\ \text{m}$$ to $$0.8\ \text{m}$$. Assume $$g=9.81\ \text{m/s}^2$$.

    • 420 s
    • 560 s
    • 680 s
    • 820 s