HGE REFRESHER

Question 1

1. What height of mercury column will cause a pressure at 690 kPa?
   A. 5.17
   B. 6.90
   C. 13.60
   D. 70.40

Answer 1

A

Question 2

2. A 1.25 cm diameter orifice, in a vertical wall of a
   tank under a constant head of 5.5 m discharged
   0.45 cubic meter in 9.5 minutes. Find the
   coefficient of discharge.
   A. 0.62
   B. 0.65
   C. 0.68
   D. 0.72

Answer 2

A

Question 3

3. A vertical jet of water thru a nozzle supports a load of 150 N. The velocity and diameter of the jet at the nozzle tip are 17.46 m/s and 3 cm. Find the distance of load from the nozzle tip in meters.
   A. 5
   B. 6
   C. 7
   D. 8

Answer 3

D

Question 4

4. A trapezoidal canal has a bottom width of 4 m and side slopes of 2 horizontal to 1 vertical. When the depth of flow is 1.2 m, the flow is 30 m3/s. The roughness coefficient n = 0.015. Evaluate the slope
   of the channel using Manning’s formula?
   A. 0.0023
   B. 0.0034
   C. 0.0045
   D. 0.0056

Answer 4

C

Question 5

5. In order to provide water from a nearby spring, a triangular flume of efficient cross-section was provided on a slope of 0.21 percent. Assuming the roughness coefficient of the channel to be n = 0.018. Obtain the depth of flow in meters of the
   water in the flume if it is discharging at the rate of 2 m3/s.
   A. 1.18
   B. 1.78
   C. 2.25
   D. 2.75

Answer 5

A

Question 6

6. An iceberg having a specific gravity of 0.90 floats in saltwater having a specific gravity of 1.03. If the volume of the ice above the surface is 500 m3, what is the volume of the iceberg in m3?
   A. 3061.5 C. 3961.5
   B. 3461.5 D. 4461.5

Answer 6

C

Question 7

SITUATION 1: A triangular gate of height 1.2 m and base 0.9 m is installed in a position that its plane is inclined 60 degrees with the horizontal with its vertex at the top and
the base is parallel to the water surface. The vertex is at a depth of 2 m vertically below the water surface. Fresh water is on one side of the gate.

7. Evaluate the total hydrostatic force on the gate, in kN.
   A. 8.76
   B. 10.8
   C. 14.3
   D. 12.6
8. Locate the point of action of the total hydrostatic force from the vertex on the plane of the gate, in m.
   A. 0.03
   B. 0.37
   C. 0.43
   D. 0.83
9. If the gate is hinged at the bottom, evaluate the force normal to the gate at its vertex that will be required to open it in kN.
   A. 4.45
   B. 5.56
   C. 6.67
   D. 7.78

Answer 7

C, D, A

Question 8

SITUATION 3: An object weighs 75 N when submerged in oil (sg=0.80) and a force of 100 N is required to hold it submerged in mercury.

13. What is the weight (N) of the object?
    A. 64.8
    B. 72.1
    C. 85.9
    D. 95.1
14. What is the volume (m3) of the object?
    A. 0.00125 C. 0.00139
    B. 0.00096 D. 0.00214
15. What is the specific gravity?
    A. 5.21
    B. 6.29
    C. 6.62
    D. 7.16

Answer 8

C, C, B

Question 8

SITUATION 2: A triangular plate of height h = 1.20 m and base b = 2 m is submerged vertically in water with its base at the liquid surface and parallel to it.

10. Evaluate the total force acting on one side of the plate, in kN.
    A. 4.08
    B. 4.21
    C. 4.32
    D. 4.71
11. Obtain the location of the force from the center of gravity of the plate, in mm.
    A. 180
    B. 190
    C. 200
    D. 210
12. Evaluate the depth of center of pressure in mm.
    A. 580
    B. 590
    C. 600
    D. 610

Answer 8

D, C, C

Question 9

16. Where is the metacenter for stable equilibrium?
    A. above center of gravity
    B. at the center of gravity
    C. below the center of gravity
    D. one half of the total draft

Answer 9

A

Question 10

17. When the metacenter of a floating body is lower than the center of gravity, then the body will be in?
    A. unstable equilibrium
    C. neutral equilibrium
    B. stable equilibrium
    D. none of the above

Answer 10

A

Question 11

18. The metacentric height is the distance between the
    A. center of gravity of the floating body and the center of buoyancy
    B. center of gravity of the floating body and the metacenter
    C. metacenter and the center of buoyancy
    D. original center of buoyancy and the new
    center of buoyancy

Answer 11

B

Question 12

19. The weight per unit volume of a liquid at a standard temperature and pressure is called:
    A. specific weight C. mass density
    B. specific gravity D. none of the above

Answer 12

A

Question 13

20. A pressure surge or wave caused when a fluid in motion is forced to stop or change direction suddenly (momentum change) is referred to in hydraulics as:
    A. hydraulic jump C. hydrodynamics
    B. potential head D. water hammer

Answer 13

D

Question 14

21. A type of shock where the flow undergoes a sudden transition from swift flow to tranquil flow.
    A. water hammer C. non-uniform flow
    B. hydraulic jump D. celerity

Answer 14

B

Question 15

22. A fluid property that measures the fluid’s resistance to shear stress.
    A. viscosity C. bulk modulus of elasticity
    B. density D. surface tension

Answer 15

A

Question 16

23. The vena contracta of a circular orifice is approximately ___ diameter downstream from the inner face of the orifice plate:
    A. 1/2
    B. 1/3
    C. 1/4
    D. 2/3

Answer 16

A

Question 17

24. When the ship’s metacenter and center of gravity coincide at same point then the vessel is said to be in:
    A. equilibrium C. unstable equilibrium
    B. stable equilibrium
    D. neutral equilibrium

Answer 17

D

Question 18

25. A force within the surface layer of a liquid that causes the layer to behave as an elastic sheet.
    A. celerity
    C. surface tension
    B. buoyant force
    D. capillarity

Answer 18

C