EXCLUSIVE FOR R.T.U.
DON’T SHARE IT TO OTHER
SCHOOL 
PIPE 1 SOLVING
PROBLEMS COACHING
NOTES
01. The refrigerant volume flow rate at the
entrance of compressor were obtained from a test
on a twin cylinder, single acting 15cm x 20cm,
320 rpm compressor ammonia refrigerating a plant
to be 33 L/s. Determine the volumetric
efficiency of the compressor.
77.65%
B. 87.6%
C. 97.6 TR
D. 65.65%
A.
02. The 600 kg hammer of a pile is
lifted 2m above the piling head. If
the hammer is released, what will be
its velocity at the instant it
strikes the piling? Local g = 9.65
m/s2
6.21 m/s
B. 3.25 m/s
C. 1.2 m/s
D. 4.5 m/s
A.
03. Compute the humidity ratio of air at
70% relative humidity and 25°C when the
barometric pressure is 101.325 kPa from
steam tables, Psat at 25°C = 3.169 kPa.
0.014 kg water vapor/kg dry air
B. 0.14 kg water vapor/kg dry air
C. 1.4 kg water vapor/kg dry air
D. 0.0014 kg water vapor/kg dry air
A.
04. Calculate the thermal diffusivity of
pure aluminum with density of 2,702
kg/m3, thermal conductivity of 237 w/m.K.
and specific heat of 0.903 kJ/kg.-K.
97.1x10-6
B. 87.5x10-6
C. 56.9x10-5
D. 88.6x10-5
A.
m2/s
m2/s
m2/s
m2/s
05. A pressure gage registers 50 psig
in a region where the barometer reads
14.8 psia. Find the absolute pressure
in kPa.
666.66
B. 556.66
C. 446.66
D. 336.66
A.
kPa
kPa
kPa
kPa
06. a new temperature scale is to be used
where freezing and boiling temperature of
water is at 100 deg. N and 500 deg. N
respectively. Calculate the absolute zero
in deg. N.
-996.8
B. -992.6
C. -994.7
D. -100.5
A.
deg.
deg.
deg.
deg.
N
N
N
N
07. Consider 1 kg of air at 32°C that expanded by a
reversible polytropic process with n = 1.25 until
the pressure is halved. Determine the heat transfer.
Specific heat at constant volume for air is 0.1786
kJ/kg °K
A.
B.
C.
D.
17.02 kJ heat rejected
17.02 kJ heat added
7.05 kJ heat rejected
7.05 kJ heat added
08. Determine the specific weight of air
at 760 mmHg absolute and 22°C.
1.024
B. 1.316
C. 1.197
D. 1.266
A.
kg/m3
kg/m3
kg/m3
kg/m3
09. A window type air conditioner is rated with
compressor power of 1 hp. The unit has an EER of
11.1. Determine the maximum cooling capacity of the
unit in tons of refrigeration.
0.54
B. 0.63
C. 0.69
D. 0.51
A.
10. A window type air conditioner is rated with
compressor power of 1 hp. The unit has an EER of
11.1. Determine the maximum cooling capacity of the
unit in tons of refrigeration.
0.54
B. 0.63
C. 0.69
D. 0.51
A.
11. Find the enthalpy of Helium if
its internal energy is 200 kJ/kg
144 kJ/kg
B. 223.42 kJ/kg
C. 333.42 kJ/kg
D. 166.0 kJ/kg
A.
12. If the conditioned space receives 80,000 kg of
air per hour and air supply temperature rises by
about 10°C and air picks up latent heat of about
150 kW. Determine the sensible heat factor of the
system.
0.597
B. 0.554
C. 0.612
D. 0.509
A.
13. Compute the mass of a 2m3 propane at
200 kPa and 40°C
6.47 kg
B. 5.1 kg
C. 10.26 kg
D. 9.47 kg
A.
14. For a certain drier, the feed has a moisture
regain of 160%. Determine the percent moisture of
the feed.
60
B. 62.43
C. 61.54
D. 50
A.
15. Compute the air flow in ft3/min of
mechanical ventilation required to exhaust
an accumulation of refrigerant due to leaks
of the system capable of revolving air from
the machinery for a mass of 49 lbs
refrigerant.
200
B. 210
C. 220
D. 230
A.
16. An amount of air with DB temperature of 35°C,
WB temperature of 28°C is passed through an air
conditioner and exhaust at a DB temperature of 24°C
and RH of 50%. Cooling coil temperature is
approximately 18°C. Determine the by-pass factor of
the air-conditioning system.
0.69
B. 0.43
C. 0.26
D. 0.35
A.
17. Compute the free aperture cross
section in m3 for the ventilation of a
machinery room if the mass of
refrigerant is 9kg.
0.314
B. 0.414
C. 0.514
D. 0.614
A.
18. A commercial air-conditioner is rated
by means of its EER or energy efficiency
ratio. For a certain air-conditioner with
a cooling capacity of 4 kW and requires
1000W, approximate EER of this unit.
13.65
B. 12.80
C. 10.10
D. 11.11
A.
19. The cooling water leaves the condenser
at 60°C and leaves the cooling tower at
35°C. The ambient air is at 35°C DB and
28°C WB. Determine the cooling tower
efficiency.
41.67
B. 80
C. 78
D. 53.33
A.
20. Compute the maximum length of the discharge
pipe installed on the outlet of a pressure-relief
device in feet for internal pipe diameter of 0.5
inch and rated discharged capacity is 0 lb/min of
air. The rated pressure of the relief valve is 16
psig.
0.286
B. 0.386
C. 0.486
D. 0.586
A.
ft.
ft.
ft.
ft.
21. A 6 stage centrifugal pump delivers
1600 gpm of water against a net pressure
rise of 800 lbf/in2. What is the specific
speed if it rotates at 1750 rpm.
A.
B.
C.
D.
248.54
952.82
1020
546.23
22. A thermal power plant has a heat rate of
11,373 BTU/kW-hr. Find the thermal efficiency
of the plant.
A.
B.
C.
D.
20%
30%
34%
40%
23. The suction pressure of a 4 stage compressor is
140 kPa. It compresses air at the rate of 15 m3/min,
clearance is about 8% and 200 rpm. The compressor
discharges compressed air at a pressure of 1000 kPa.
If the compressor uses inter cooling determine the
ideal pressure at the first stage intercooler.
228.87
B. 345.67
C. 453.45
D. 345.45
A.
kPa
kPa
kPa
kPa
24. Find the heat needed to raise the temperature of
water from 30°C to 100°C with 60% quality.
Consider an atmospheric pressure of 101.325 kpa. Use
the approximate enthalpy formula of liquid.
293.09 Kj/kg.
B. 1772.91 Kj/kg.
C. 1547.90 Kj/kg.
D. 1647.29 Kj/kg.
A.
25. A Pelton wheel running at a speed of 600 rpm
is driven by 2 similar jets. At this speed it
transmits 6000 kW to the shaft. The efficiency of
the runner is 90% and the velocity of the fluid at
inlet to the bucket is 50 m/sec. Estimate the
diameter of each jet.
A.
B.
C.
D.
0.0165
0.0435
0.0143
0.0123
m
m
m
m
26. An air compressor consumed 1200 kw-hr.
per day of energy. The electric motor
driving the compressor has an efficiency
of 80%. If indicated power of compressor
is 34 kw, find the mechanical efficiency
of the compressor.
117.65%
B. 75%
C. 85%
D. 90%
A.
27. A steam generator operating at 92%
efficiency leaves water at 15.6°C while
steam leaves the super heater at h = 3374.8
kJ/kg. Estimate the evaporation factor if
the boiler consumes coal of calorific value
24,500 kJ/kg.
6.81
B. 6.72
C. 8.21
D. 7.21
A.
m
m
m
m
28. A refrigeration system consumed 28,800 kw-hr
per month of energy. There are 20% of energy is
lost due to cooling system of compressor and motor
efficiency is 90%. If COP of the system is 6, find
the mechanical efficiency of the compressor.
43.15
B. 46.15
C. 49.15
D. 41.15
A.
TR
TR
TR
TR
29. A 23 tons refrigeration system
has a heat rejected of 100kw. Find
the energy efficiency ratio of the
system.
13.42
B. 14.42
C. 15.42
D. 16.42
A.
30. Calculate the available pressure
head for natural circulation in the
10m riser if the specific volume in
the downcomer is 0.0014 and in the
riser top is 0.0032 m3/kg.
19.71
B. 12.45
C. 21.45
D. 15.74
A.
kPa
kPa
kPa
kPa
31. A 200mm x 250 mm, 8-cylinder, 4-stroke
diesel engine has a brake power of 150 kw.
The mechanical efficiency is 80%. If two
of the cylinders were accidentally cut off,
what will be the new friction power?
31.50
B. 33.50
C. 35.50
D. 37.50
A.
kw
kw
kw
kw
32. Estimate the circulation ratio in the downcomer
riser circuit when the mass of saturated water
flowing through it is 10 kg/sec, while at the riser
exit saturated liquid water flows at 8.5 kg/sec.
A.
B.
C.
D.
1.18
6.67
5.9
0.85
33. If the energy efficiency ratio of the
refrigeration system is 12.6, what is the COP
of the system?
3.69
B. 4.23
C. 5.92
D. 6.83
A.
34. The two phase flow in a riser has volume
quality and moisture of 0.60 and 90%
respectively. If the ratio of the specific
volume of vapor to that of the liquid is 20,
estimate the slip ratio.
A.
B.
C.
D.
1.48
1.67
1.74
1.32
35. An air compressor has a power of 40kw at
4% clearance. If the clearance will increase
to 7%, what is the new power?
A.
B.
C.
D.
70
40
53
60
kw
kw
kw
kw
36. Determine the net cycle heat rate of
a steam power plant with a gross cycle
heat rate of 75% and the ratio of turbine
output to net cycle output is 1.11
83.25%
B. 76.25%
C. 87.45%
D. 80.76%
A.
37. What is the approximate value of
temperature of water having enthalpy of 208
Btu/lb?
138.67
B. 115.55
C. 258.67
D. 68.67
A.
38. Two kilogram of air in a rigid tank changes its
temperature from 32°C to 150°C. Find the work done
during the process.
236
B. 170
C. 195
D. 0
A.
39. Determine the atmospheric pressure at a
location where barometric reading is 740 mm
Hg and gravitational acceleration is
g=9.7m/s2. Assume the temperature of mercury
to be 10°C, at which the density is 13,570
kg/m3.
99.45
B. 97.41
C. 95.44
D. 98.66
A.
kpa
kpa
kpa
kpa
40. A reverse Carnot cycle air refrigeration
equipment has a compressor working with a
compression ratio of 12. The temperature
limits of the cycle are 300K and 270K.
Determine the refrigerating effect of the
unit.
2.45
B. 1.86
C. 2.06
D. 1.26
A.
TR
TR
TR
TR
41. The barometer of a mountain hiker reads
930 mbars at the beginning if a hiking trip
and 780 mbars at the end. Neglecting the
effect of altitude, on local gravitational
acceleration, determine the vertical
distance climbed. Assume g=9.7 m/s2.
1274.21
B. 1289.00
C. 1267.34
D. 1583.34
A.
m
m
m
m
42. A refrigeration system produce
20kg/hr of ice from water at 20
deg°C. find the tonnage of unit
0.66
B. 0.55
C. 0.77
D. 0.88
A.
43. The lower half of a 10 m high
cylindrical container is filled with water
and the upper half with oil that has
SG=0.85. Determine the pressure difference
between the top and bottom if the cylinder.
90.74
B. 92.74
C. 83.88
D. 98.10
A.
kpa
kpa
kpa
kpa
44. About 3hp per ton is required to maintain a
temperature of -40°C in a refrigerator. If the
refrigerator works on the reverse carnot cycle,
determine the heat rejected to the sink per ton of
refrigeration.
69.72
B. 70.24
C. 81.61
D. 84.65
A.
kCal/min
kCal/min
kCal/min
kCal/min
45. An ideal gas at 0.80 atmospheres and
87°C occupies 0.450 liter. How many moles
are in the sample? (R=0.0821 literatm/mole-K)
0.0002
B. 0.0378
C. 0.0122
D. 0.0091
A.
mole
mole
mole
mole
46. Determine the mass of ice produce from
water per day for the following conditions:
Water temperature 22°C, tonnage of the
unit 150 tons, operating temperatures -5°C
and 28°C, latent heat of ice 330 kJ/kg.
107,498
B. 120,465
C. 134,112
D. 140,362
A.
kg
kg
kg
kg
47. A certain gas at 101.325 Kpa and 10°C whose
volume is 2.83 m3 capacity. Before admission, the
storage vessel contained gas at a pressure and
temperature of 137.8 Kpa and 26 after admission, the
pressure increased to 1171.8 Kpa. What should be the
final temperature of the gas in the vessel in Kelvin?
A.
B.
C.
D.
298.0
319.8
180.0
314.2
48. A cold storage is required to store 20 tons of fish.
The fish is supplied at a temperature of 30°C. The
specific heat of fish above the freezing point is 2.93
kJ/kg-K. The specific heat of fish below freezing point is
1.26 kJ/kg-K. The fish is stored in cold storage that is
maintained at -8°C. The freezing point of the fish is 4°C. The latent heat of solidification of the fish is 235
kJ/kg. If the plant requires 75kW to drive it, find the
time taken to achieve cooling. Assume the actual COP as
0.3 times the Carnot COP of the refrigerating plant.
14.72 hrs
B. 9.64 hrs
C. 10.41 hrs
D. 12.03 hrs
A.
49. A perfect gas has a value of R=58.8 ft-lb/lb-°R
and k=1.26. If 20 Btu are added to 10 lbs of this
gas at constant volume when initial temperature is
90°F, find the final temperature.
97
B. 104
C. 154
D. 185
A.
50. A research laboratory building is to be heated and
ventilated. Air is to be supplied to a room 12m x 18m
from the outside at the rate of 1 m3/min air replacement
for each square meter of floor space. The design
condition includes 20°C room temperature and -20°C
outside air temperature. In addition the pressure in the
room is to be maintained at a positive pressure of 7 kPa
to ensure that there will be no air leakage into the
laboratory. How much heat would be required to condition
the air for this room?
A.
B.
C.
D.
177.11 kW
154.8 kW
168.7 kW
185.3 kW
51. A 3 hp refrigerator or heat pump
operates between 0°F and 100°F. The
maximum theoretical heat that can be
transferred from the cold reservoir is
nearest to:
A.
B.
C.
D.
1300 Btu/hr
2300 Btu/hr
35000 Btu/hr
43000 Btu/hr
52. At 1.3MPa, mixture steam and water
has an entropy if 3 kJ/kg- oK, Find the
enthalpy of the mixture.
At 1.3MPa:
sf= 2.2515, sg= 6.4952, hf= 814.93, hfg=
1972.7
1627.71
B. 1533.33
C. 1234.45
D. 1162.40
A.
kJ/kg
kJ/kg
kJ/kg
kJ/kg
53. A block of wood floats in water with 6 inches
projecting above the water surface. If the same
block were placed in alcohol of specific gravity of
0.82, he block would project 4 inches above the
water surface of alcohol. Determine the of the wood
block.
0.603
B. 0.504
C. 0.701
D. 0.243
A.
54. Mixture with 70% quality at 50 kPa is
heated isothermally until its pressure is 300
kPa. Find the heat added during the process.
At 600 kPa: sf = 1.8607, sfg = 4.9606
At 300kPa and 151.86 oC:
s= 7.0888 kJ/kg
A.
B.
C.
D.
745.92
535.16
982.44
765.34
kJ/kg
kJ/kg
kJ/kg
kJ/kg
55. A tank contains exactly one kilogram of water
consisting of liquid and vapor in equilibrium at 1
Mpa. If the liquid contains one-third and the
remaining is vapor of the tank, what is the enthalpy
of the contents of the tank.
At 1MPa:
vf = 0.0011273, vfg = 0.19444
hf = 762.81, hfg = 2015.3
644.40
B. 774.40
C. 785.92
D. 435.29
A.
kJ/kg
kJ/kg
kJ/kg
kJ/kg
56. A cylinder 10ft long and 2ft in diameter is
suspended in air flowing at 8 ft/sec. The density
of air is 0.00234 slug/ft3 and the coefficient of
drag of the sphere is 1.3. What is the drag on the
cylinder?
0.39 lbf
B. 1.95 lbf
C. 4.99 lbf
D. 0.311 lbf
A.
58. The Reynolds number of a sphere
falling in air is 1 x 106. If the
sphere’s radius is 1ft, what is its
velocity?
2.5 ft/sec
B. 5.1 ft/sec
C. 40.6 ft/sec
D. 81.2 ft/sec
A.
57. Water substance at 70 bar and 65oC enters a
boiler tube of constant inside diameter of 25mm. The
water leaves the boiler tube at 50 bar and 700oK at
velocity of 150 m/s. Calculate the inlet velocity
(m/sec).
From steam tables:
At 70 bar
v1 =
At 50 bar
v2 =
A.
B.
C.
D.
(7Mpa) and 65oC:
0.001017 m3/kg
(5Mpa) and 700oK(427oC):
0.06081 m3/kg
1.56
2.51
1.672
3.230
59. Water substance at 70 bar and 65oC enters a boiler
tube of constant inside diameter of 35mm. The water
leaves the boiler tube at 50 bar and 700oK at velocity
of 150 m/s. Calculate the inlet volume (m/sec).
From steam tables:
At 70 bar (7Mpa) and 65oC:
v1 = 0.001017 m3/kg
At 50 bar (5Mpa) and 700oK(427oC):
v2 = 0.06081 m3/kg
0.821
B. 1.261
C. 0.344
D. 1.609
A.
60. Steam leaves an industrial boiler at 827.4 kPa
and 171.6oC. A portion of the steam is passed through
a throttling calorimeter and is exhausted to the
atmosphere when the calorimeter pressure is 101.4
kPa. How much moisture does the steam leaving the
boiler contain if the temperature of the steam at
the calorimeter is 115.6oC?
At~
3.78%
B. 3.08%
C. 4.56%
D. 2.34%
A.
61. Three liquids of specific gravities
0.7, 0.8 and 0.9 respectively are mixed
in the proportion of 3, 4, and 5 by mass.
Find the relative density of the mixture.
0.81
B. 0.62
C. 0.73
D. 0.92
A.
62. Atmospheric pressure boils at 212oF. At
the vacuum pressure at 24 in Hg, the
temperature is 142oF. Find the boiling
temperature when the pressure is increased
by 40 psia from atmospheric.
449.42
B. 536.34
C. 479.13
D. 263.45
A.
64. A vertical bulkhead 9.6m wide and
6m deep separates two tanks. One tank
contains oil of relative density of
0.8 to a depth of 4.2m. Find the
total head of the bulkhead in MN.
1.472
B. 2.013
C. 1.168
D. 2.347
A.
63. A certain coal has the following
ultimate analysis:
C= 69%
N2 = 5%
H = 2.5%
S =7%
Determine the amount of oxygen if the
heating values of fuel is 26,961.45 kJ/kg.
A.
B.
C.
D.
1.5%
2.5%
3.5%
4.5%
65. A throttling calorimeter is
connected to the desuperheated steam
line supplying steam to the auxiliary
feed pump on a ship. The line pressure
measures 2.5 Mpa. The calorimeter
pressure is 110 kPa and 150oC. Determine
the entropy of the steam line.
At~
A.
B.
C.
D.
6.8
6.2
6.6
7.5
kJ/kg-°K
kJ/kg-°K
kJ/kg-°K
kJ/kg-°K
66. A logging firm in Isabella operates a Diesel
Electric Plant to supply its electric energy
requirements. During a 24 hour period, the plant
consumed 250 gallons of fuel at 80oF and produced
2900 KW-hrs. industrial fuel used is 30 API and
was purchased at P30.00/li at 60F. Determine the
overall thermal efficiency of the plant.
26.08%
B. 34.23%
C. 28.00%
D. 18.46%
A.
67. The following coal has the following ultimate
analysis by weight:
C = 70.5%
H2 = 4.5%
O2 = 6.0%
N2 = 1.0%
S = 3.0%
Ash = 11%
Moisture = 4%
A stocker fired boiler of 195,000 kg/hr steaming
capacity uses this coal as fuel. Calculate volume
of air in m3/hr with air at 60oF and 14.7 psia
pressure if boiler efficiency is 70% and FE = 1.10
234,019
B. 215,830
C. 213,830
D. 264,830
A.
m3/hr
m3/hr
m3/hr
m3/hr
68. A windmill with a 6m radius rotor is to be
installed where atmospheric pressure conditions
prevail at 101.325 kPa and 21°C. It was
observed that wind is blowing steadily at an
average velocity of 20 m/sec. Assuming that the
conversion efficiency is somewhere between 20%
to 25%, determine the maximum available power
from the windmill.
124.78
B. 135.81
C. 167.25
D. 225.78
A.
kW
kW
kW
kW
69. 23.5 kg of steam per second at 5 Mpa and 400oC is
produced by a steam generator. The feed water enters
the economizer at 145oC and leaves at 205oC. The steam
leaves the boiler drum with a quality of 98%. The unit
consumes 3 kg of coal per second as received having
value of 25,102kJ/kg. What would be the overall
efficiency of the unit in percent?
Steam properties~
65.72
B. 80.67
C. 88.28
D. 78.82
A.
70. In a Rankine cycle steam enters the turbine at
2.5 Mpa (enthalpies & entropies given) and
condenser of 50 Kpa (properties given), what is the
thermal efficiency of the cycle?
At~
25.55%
B. 45.23%
C. 34.23%
D. 12.34%
A.
71. A thermal power plant generates 5 MW
and the heat generated by fuel is 13,000
kJ/sec. If the thermal efficiency is
35.15%, find the power needed for the
auxiliaries.
510
B. 300
C. 400
D. 350
A.
kw
kw
kw
kw
72. A superheat steam Rankine cycle has turbine
inlet conditions of 17.5 Mpa and 530oC expands
in a turbine to 0.007 Mpa. The turbine and pump
polytropic efficiencies are 0.85 and 0.75
respectively. Pressure losses between the pump
and turbine inlet are 1.5 Mpa. What should be
the pump work in kJ/kg?
17.34
B. 27.32
C. 25.32
D. 47.33
A.
73. In an open feed water heater for a steam plant,
saturated steam at 7 bar is mixed with sub cooled
liquid at 7 bar and 25oC. Just enough steam is
supplied to ensure that the mixed steam leaving the
heater will be saturated liquid at 7 bar when
heater efficiency is 95%. Calculate the mass flow
rate of the sub cooled liquid if steam flow rate is
0.865 kg/s
Steam properties~
2.725
B. 3.356
C. 2.869
D. 3.948
A.
kg/s
kg/s
kg/s
kg/s
74. A steam condenser receives 10 kg/s of
steam with an enthalpy of 2770 kJ/kg. Steam
condenses and leaves with an enthalpy of
160 kJ/kg. Cooling water passes through the
condenser with temperature increases from
13 degrees C to 24oC. Calculate the water
flow rate in kg/s.
583
B. 567
C. 523
D. 528
A.
75. Steam expands adiabatically in a
turbine from 2000 kPa, 400oC to 400 kpa,
250 oC. What is the effectiveness of the
process in percent assuming an atmospheric
pressure of 18oC. Neglect changes in
kinetic and potential energy.
Steam properties~
A.
B.
C.
D.
82
84
79.60
79.46
76. The annual peak load on a 15,000 kW power
plant is 10,500 kW. Two substations are
supplied by this plant. Annual energy
dispatched through substation A is 27,500,000
kW-hr with a peak load at 8,900 kW, 16,500,000
are sent through substation B with a peak load
at 6,650 kW. Neglect line losses. Find the
diversity factor between substations and
capacity factor of the power plant.
1.48,
B. 1.48,
C. 1.75,
D. 1.75,
A.
0.446
0.335
0.335
0.446
77. A heat exchanger was installed
purposely to cool 0.50kg of gas per second.
Molecular weight is 32 and k = 1.32. The
gas is cooled from 150oC to 80oC. Water is
available at the rate of 0.30 kg/s and at
a temperature of 15oC. Calculate the exit
temperature of the water in oC.
44.86
B. 42.86
C. 46.45
D. 40.34
A.
78. An impulse wheel at best produces
125 hp under a head of 210ft. By what
percent should the speed be increased
for a 290-ft head?
A.
B.
C.
D.
82.5%
17.5%
72.41%
27.59%
79. Find the work possess for a helium gas at 20°C?
609
B. 168
C. 229
D. 339
A.
KJ/kg
KJ/kg
KJ/kg
KJ/kg
80. A horizontal jet fresh water 40mm diameter
impinges on a stationary flat plate which is
perpendicular to the jet, and the direct force to
prevent the plate moving is measured to be 225 N.
Assuming that there is no splash back of water, find
the initial velocity of the jet.
13.39
B. 12.42
C. 16.21
D. 14.34
A.
m/sec
m/sec
m/sec
m/sec
81. What is the hydraulic gradient of 1
mile, 17 inches inside diameter pipe
when 3300 gal/min of water flow with
f=0.03.
0.00714
B. 0.00614
C. 0.00234
D. 0.00187
A.
82. Convert 750°R to °K.
390.33°K
B. 395.33°K
C. 410.33°K
D. 416.33°K
A.
83. Air is compressed adiabatically from
30°C to 100°C. If mass of air being
compressed is 5 kg. Find the change in
entropy
1.039 kJ/°K
B. 0.746 kJ/°K
C. 0
D. 1.245 kJ/kg
A.
84. The sun generates an averages of 2
kW/m2 when tapped as source of energy
where in a flat plate collector with an
area of 1.5 m2 is used. Flow rate of
water inside the collector is 40 liters
per hour. Calculate for the temperature
rise of the working fluid in °C
65.14
B. 60.15
C. 55.14
D. 50.15
A.
°C
°C
°C
°C
85. An air standard engine has a compression ratio
of 18 and a cut-off ratio of 4. If the intake air
pressure and temperature are 100 kPa and 27°C, find
the work in kJ per kg.
2976
B. 2166
C. 1582
D. 2751
A.
86. A diesel engine consumed 645 liters of fuel per
day at 35°C. If the fuel was purchased at 15.5°C
and 30°API at P 29.00 per liter, determine the
cost of fuel to operate the engine per day.
P
B. P
C. P
D. P
A.
5,677.50
4,577.50
46,080.90
27,127.76
87. A cylindrical tank 4m long and 3m
diameter is used for oil storage. How
many days can the tank supply the engine
having 27°API with fuel consumption of 60
kg/hr?
17.53
B. 5.84
C. 12.84
D. 19.84
A.
88. The dry exhaust gas from oil engine has the
following gravimetric analysis:
CO2 = 21.6% O2 = 4.2%
N = 74.2%
Specific heats at constant pressure for each
component of the exhaust gas in Kcal/kg-oC are:
CO2 = 0.203 O2 = 0.209 N = 0.248
Calculate the specific gravity if the molecular
weight of air is 28.97kg/kg-mol
0.981
B. 1.244
C. 1.055
D. 0.542
A.
89. A bituminous coal has the following
composition:
C = 71.5%
H = 5.0% O = 7.0%
N = 1.3%
S = 3%
Ash = 7.6%
W = 3.4%
Determine the theoretical weight of
Nitrogen in lb/lb of coal.
2.970
B. 7.526
C. 2.274
D. 6.233
A.
90. A gaseous fuel mixture has a molal analysis:
H2 = 14%
CH4 = 3%
CO = 27%
O2 = 0.6% CO2 = 4.5% N2 = 50.9%
Determine the air-fuel ration for complete
combustion on molal basis
2.180
B. 3.230
C. 1.233
D. 1.130
A.
91. Fresh water flows through a short
smooth horizontal pipe of tapered bore.
At the large end the velocity is 1.5 m/s.
At the small end the pressure is 14 kN/m2.
Calculate the velocity at this end.
4.4
B. 5.5
C. 6.6
D. 3.3
A.
m/sec
m/sec
m/sec
m/sec
92. A volumetric analysis of a gas mixture is a
follows:
CO2
:
12%
O2
:
4%
N2
:
80%
CO
:
4%
What percentage of CO2 on a mass basis?
17.55%
B. 15.55%
C. 12.73%
D. 18.73%
A.
93. What should be the cooling requirement due to
emission of body to maintain a comfortable temperature
in a dance hall that had an attendance of 1500 people
if it has been determined that 75% of the people will
be dancing and others will be seated. Test have shown
that an adult will give off 71.8 W of sensible heat
while engaging in moderate dancing and 57.1 W of
sensible heat while sitting. The latent heat emissions
for similar situations have been found to equal 177.3
W for dancers and 45.5 W for sitters.
200
B. 267
C. 301
D. 319
A.
kW
kW
kW
kW
94. A refrigeration plant is rated at
15tons capacity. How many pounds of
air per hour will it cool from 70 to
90°F at constant temperature?
50,000lb/hr
B. 37,500lb/hr
C. 52,000lb/hr
D. 45,000lb/hr
A.
95. A refrigerator is rated at a USA one ton
capacity. It maintains a cooling temperature of
4.4°C (evaporator temperature). A refrigerant with
a refrigerating effect of 136 kJ/kg is in the
condenser just ahead of the expansion valve. If the
refrigerant vapor has a density of 19.80 kg/m3,
what should be the capacity of the compressor?
A.
B.
C.
D.
0.078
0.091
0.102
0.113
m3/min
m3/min
m3/min
m3/min
96. Determine the air-standard efficiency of
an engine operating on the diesel cycle with
clearance of 6% when the suction pressure is
99.7 kPa and the fuel is injected for 7% of
the stroke. Assume K= 1.4
62.11
B. 51.20
C. 73.58
D. 60.02
A.
%
%
%
%
97. An engine operating on a Carnot cycle
between temperatures of 500°C and 30°C
produces 50 kJ of work. What change in
entropy occurs during the heat rejection
portion of the cycle?
106.4
B. 160.4
C. 120.5
D. 102.5
A.
J/K
J/K
J/K
J/K
98. Steam at 2 Mpa and 250oC in a rigid
cylinder is cooled until the quality is 30%.
Find the heat rejected from the cylinder.
At 2Mpa and 250oC:
v = 0.11144 m3/kg
u=2679.6 KJ/kg
At 2Mpa, (saturated):
vf = 0.0011767 m3/kg, vg = 0.09963 m3/kg,
uf = 906.44kJ/kg, ug = 1693.8 kJ/kg
A.
B.
C.
D.
-423.23 kJ/kg
-926.26 kJ/kg
-1265.02 kJ/kg
1082.34 kJ/kg
99. Ammonia weighing 22 kgs is confirmed inside a
cylinder equipped with a piston has an initial
pressure of 413 Kpa at 38°C. If 3200 KJ of heat
is added to the ammonia until its final pressure
and temperature are 413 Kpa and 100°C,
respectively, what is the amount of work done by
the fluid in KJ?
A.
B.
C.
D.
667
304
420
502
100. A refrigeration system produce
20kg/hr of ice from water at 20 deg°C.
find the tonnage of unit
A.
B.
C.
D.
0.66
0.55
0.77
0.88
101. A tank contains 90ft3 of air at a
pressure of 350 psig; if the air is cooled
until its pressure and temperature
decreases at 200 psig and 70°F
respectively, what is the decrease in
internal energy?
A.
B.
C.
D.
6232.09 Btu
-5552
5552
-6232.09 Btu
102. About 3hp per ton is required to maintain a
temperature of -40°C in a refrigerator. If the
refrigerator works on the reverse Carnot cycle,
determine the heat rejected to the sink per ton of
refrigeration.
69.72
B. 70.24
C. 81.61
D. 84.65
A.
kCal/min
kCal/min
kCal/min
kCal/min
103. A large mining company was provided
with a 3 m3 of compressed air tank. Air
pressure in the tank drops from 700 kPa
to 150 kPa while the temperature remains
constant at 28°C. What percentage has the
mass of air in the tank been reduced?
A.
B.
C.
D.
74
72.45
78.56
78.57
104. Determine the mass of ice produce from water
per day for the following conditions: Water
temperature 22°C, tonnage of the unit 150 tons,
operating temperatures -5°C and 28°C, latent
heat of ice 330 kJ/kg.
107,498
B. 120,465
C. 134,112
D. 140,362
A.
kg
kg
kg
kg
105. A 4 m3/hr pump delivers water to a pressure
tank. At the start, the gage reads 138 kPa until it
reads 276 kPa and then the pump was shut off. The
volume of the tank is 180 liters. At 276 kPa the
water occupied 2/3 of the tank volume. Determine
the volume of water that can be taken out until the
gage reads 138 kPa.
31.20
B. 34.59
C. 16.67
D. 29.50
A.
liters
liters
liters
liters
106. A rectangular duct 0.15m by 0.12 long
and carries standard air at the rate of 0.3
m3/sec. Calculate the total pressure
required at the inlet to the duct in order
to maintain this flow. Assume that for this
duct, the friction factor is 0.005.
567.58
B. 671.85
C. 851.67
D. 716.58
A.
N/m2
N/m2
N/m2
N/m2
107. A 10-stages air compressor
compresses air from 100 kPa to 1000 kPa.
Find the intercooler pressure between
the first and second stage.
282.84
B. 113.21
C. 123.11
D. 333.51
A.
kPa
kPa
kPa
kPa
108. A circular duct of 40cm is selected to carry
air in an air-conditioned space at a velocity of 440
m/min to keep the noise at desired level. If this
duct is replaced by a rectangular duct 2.5, find the
size of rectangular duct for equal friction method
when the velocity of air in two ducts is same.
A.
B.
C.
D.
45cm
40cm
50cm
30cm
x
x
x
x
30cm
25cm
35cm
15cm
109. A 3-stages air compressor compresses
air from 100 kPa to 700 kPa. Find the
intercooler pressure between the second
and third stage.
365.88
B. 375.88
C. 385.88
D. 395.88
A.
kPa
kPa
kPa
kPa
110. A galvanized steel duct of 0.4m
diameter and 20m long carriers air at
20°C and 1.013 bar. If the surface
roughness for the duct is 0.15mm,
find the roughness factor.
A.
B.
C.
D.
0.000475
0.000365
0.000375
0.000485
111. Carnot cycle A, B, and C are connected in
series so that the heat rejected from A will be
the heat added to B and heat rejected from B
will be added to C, each cycle operates between
30°C and 400°C. If heat added to A is 1000 kW,
find the heat output of C.
111.44
B. 549.78
C. 247.53
D. 141.69
A.
kW
kW
kW
kW
112. A reverse Carnot cycle air conditioner of 4
TR capacity operates with a cooling coil of
temperature of 5°C. The surrounding air at 45°C
is used as a cooling medium rising to the
temperature of 55°C. The temperature of heat
rejection is 60°C. Determine the mass flow rate
of air entering the heat exchanger.
0.07
B. 0.12
C. 0.16
D. 0.04
A.
kg/sec
kg/sec
kg/sec
kg/sec
113. What is the over all efficiency of a
30 MW steam power plant with a boiler
efficiency of 92%. Cycle efficiency of
44%, mechanical loss of 5%, generator
efficiency of 93% and gross power
production of 32000kW.
33.98%
B. 36.88%
C. 35.44%
D. 38.84%
A.
114. An Otto cycle has a compression ratio of
8, Find the pressure ratio during compression.
18.38
B. 16.38
C. 14.38
D. 12.38
A.
115. The downcorner riser circuits
receive saturated water a rate of
10.5 kg/s from the boiler. If the
circulation ratio is 11.5, what is
the top dryness fraction?
0.095
B. 0.087
C. 0.081
D. 0.913
A.
116. A diesel cycle has a cut off ratio of 2.5
and expansion ratio if 4. Find the clearance of
the cycle.
9.11%
B. 5.55%
C. 11.11%
D. 15.15%
A.
117. A circular cylinder 4ft long and 3ft
in diameter is in an air stream. The flow
velocity is 5 ft/sec perpendicular to the
axis of the cylinder. Given that the
coefficient of drag on the cylinder is 1.3
and the density of air is 0.00234 slug/ft3.
What is the force in the cylinder?
0.09
B. 0.11
C. 0.46
D. 0.91
A.
lb
lb
lb
lb
119. A rectangular duct section 35cm x
50cm size carries 75 m3/min of air having
density of 1.15 kg/m3. If the friction
power of sheet metal is 0.01, find the
pressure loss per 100m length of duct.
A.
B.
C.
D.
29
36
25
35
mm
mm
mm
mm
of
of
of
of
H2O
H2O
H2O
H2O
118. A dual cycle has an initial
temperature of 30°C. The compression
ratio is 6 and the heat addition at
constant volume process is 600 kJ/kg/ If
cut-off ratio is 2.5, find the maximum
temperature of the cycle.
A.
B.
C.
D.
3638.50°C
3365.50°C
3565.50°C
3965.50°C
120. A three stages air compressor air from
100 kPa to 1000 kPa. Find the intercooler
pressure between the first and second stage.
A.
B.
C.
D.
505.44 kPa
108.44 kPa
316.23 kPa
215.444 kPa
121. Find the pressure at the 100
fathom depth of water in kPag
1,793.96
B. 1,893.96
C. 1,983.96
D. 1,693.96
A.
kPag
kPag
kPag
kPag
122. Air flows in a duct at pressure of 150
kPa with a velocity of 200 m/s. The
temperature of the air is 310K. Determine the
isentropic stagnation temperature
A.
B.
C.
D.
320
332
341
361
124. A Pelton wheel running at a speed of 400
rpm is driven by a water power of 5000 kW. The
elevation is 150 m and the velocity coefficient
is 0.97. Find the number of jets required if its
diameter is limited at 0.15 m.
A.
B.
C.
D.
3
4
5
6
123. Find the depth in furlong of the
ocean (S.G. = 1.03) if the pressure
at the sea bed is 2,032.96 kPag
1
B. 2
C. 3
D. 4
A.
125. Find the mass of ten quartz of
water
10.46 kg
B. 9.46 kg
C. 11.46 kg
D. 8.46 kg
A.
126. A 18,000 kW geothermal plant has a generator
efficiency and turbine efficiency of 90% and 80%
respectively. If the quality after throttling is
20% and each well discharges 400,000 kg/hr,
determine the numbers of wells are required to
produce if the change of enthalpy at entrance and
exit of turbine is 500 kJ/kg
4
B. 2
C. 6
D. 8
A.
wells
wells
wells
wells
127. Find the mass of carbon dioxide
having a pressure of 20 psia at
200°F with 10 ft3 volume.
1.04
B. 1.14
C. 1.24
D. 1.34
A.
lbs
lbs
lbs
lbs
128. Calculate the scale ratio for the model
turbine if the prototype to model speed and head
ratio is 0.675 and 12 respectively.
5.54
B. 5.13
C. 5.82
D. 5.32
A.
129. Find the loss of head in the pipe
entrance if speed of flow is 10 m/s
5.10
B. 10.2
C. 17.4
D. 2.55
A.
m
m
m
m
130. Find the COP of the refrigerator
whose energy supply equals one fourth
the amount of heat it extracts.
3
B. 4
C. 5
D. 2
A.
131. Wet material containing 220% moisture
(dry basis) is to be dried at the rate of
1.5 kg/s in a continuous dryer to give a
product containing 10% (dry basis). Find
the moisture removed.
3545.75
B. 3513.75
C. 3563.75
D. 3563.75
A.
kg/hr
kg/hr
kg/hr
kg/hr
132. An air-conditioning engineer has given
the following data to be air conditioned:
room sensible heat gain 50,000 Btu/hr. Room
latent heat gain 10,000 Btu/hr. Outside
condition 95°F DB and 75°F WB, inside
condition 50°F. Calculate the
refrigeration tonnage required with 10%
safety factor.
5.5
B. 3.5
C. 1.5
D. 6.5
A.
133. Copra enters a dryer containing 70%
moisture and leaves at 7% moisture. Find
the moisture removed on each pound of
solid in final product.
A.
B.
C.
D.
6.258
1.258
4.258
2.258
lb
lb
lb
lb
134. If the specific heat at P=C, for CO2 is 0.201
BTU/lb-R. What is the value of the specific heat at
V=C?
0.756
B. 1.876
C. 3.234
D. 0.156
A.
BTU/lb-R
BTU/lb-R
BTU/lb-R
BTU/lb-R
135. A 1m x 1.5m cylindrical tank is
full of oil with SG = 0.92. Find the
force acting on the bottom of the
tank in dynes.
106.33
B. 106.33
C. 106.33
D. 106.33
A.
x
x
x
x
103
104
105
106
dynes
dynes
dynes
dynes
136. An amount of 400 BTU of heat is transfer from
a reservior at 800 deg. F to a reservior at 200 F,
find change in S of the system.
2.89
B. 8.54
C. 2,78
D. 3.21
A.
137. The filament of a 100 W bulb maybe
considered a blackbody radiating into a
black enclosure into a black enclosure at
80 ºC. Considering only radiation,
calculate the filament temperature in deg.
C, if the filament diameter is .10 mm. and
the length is 6 cm.
4598
B. 2837
C. 6564
D. 5643
A.
deg.
deg.
deg.
deg.
C
C
C
C
138. A heat engine has a thermal efficiency of
50%. How much power does the engine produce
when heat is transferred at the rate of 109
kJ/hr?
50 MW
B. 75 MW
C. 139 MW
D. 147 MW
A.
139. A circular chip (k=150 W/m-K) with a diameter
10 mm. and thickness 4 mm. is embedded in a circuit
board. It's front surface is exposed to the flow of
coolant (h=250 W/m2-K) with temperature of 10 deg.
C, while its side and black surfaces are perfectly
insulated. If at any point in the chip the
temperature must not exceed 90 deg. C, what is the
steady state heat dissipation of the chip?
3.85
B. 1.56
C. 2.33
D. 6.96
A.
W
W
W
W
141. A 1kg steel (C = 0.5 kJ/kg-K) rivet
cools from 800K to 300K upon being
installed in a riveted structure. The
entropy change in kJ/kg-K of this rivet
is:
-0.245
B. -0.49
C. -0.631
D. -0.546
A.
140. One kilogram of air is compressed
adiabatically and in a steady-flow manner.
The compression efficiency is 80% and the
work done on the air is 265 kJ/kg.
Compute the heat.
A.
B.
C.
D.
212 kJ/kg
100 kJ/kg
0 kJ/kg
331.25 kJ/kg
142. Three hundred kilojoules of heat flow
by conduction from the outside to the
inside of a cold storage in one hour. If
the temperature and all other conditions
are the same, what is the heat flowing
through the cold storage room in two hours?
600 kJ
B. 900 kJ
C. 300 kJ
D. 1200 kJ
A.
143. The heat pump has a performance
factor of 8.0. If the heat pump is used
as a refrigerator, what is the required
horsepower per ton of refrigeration?
0.942
B. 0.456
C. 0.765
D. 0.673
A.
144. An elastic sphere containing gas at
120 kPa has a diameter of 1m. Heating the
sphere causes it to expand to a diameter
of 1.4m. During the process the pressure
is proportional to the sphere diameter.
Calculate the work done by the gas.
A.133.92kJ
B.133.91kJ
C.133.94kJ
D.133.91kJ
145. Fifty kilograms of cooling water per
second enter the condenser at 25°C and
leaves at 50°C. find the heat carried
away from water
A.
B.
C.
D.
1234.45
5233.75
2340.53
3140.25
kW
kW
kW
kW
146. Ten kilograms per seconds of steam
enter the turbine with an enthalpy of 3200
kJ/kg and enter the condenser with an
enthalpy of 2500 kJ/kg in a Rankine cycle.
If the turbine efficiency is 90% and the
generator efficiency is 90%, determine the
power plant output.
4320
B. 3213
C. 4056
D. 5040
A.
kW
kW
kW
kW
147. Air is used in a Carnot engine where the
volumes at the beginning of the constant
temperature heat addition and end of constant and
6.73 cm2 respectively. Calculate the thermal
efficiency.
A.0.566
B.0.665
C.0.656
D.1.566
148. Determine the quality of steam in a
vessel containing 2 kg of saturated vapor
and 8 kg of saturated liquid
100%
B. 20%
C. 80%
D. 60%
A.
149. What is the litting force in kN for a
16m diameter spherical balloon with helium
inside at 101 kPa and 320 K surrounded by
air at 101 kPa and 298.15 K?
A.5.28
B.3.54
C.8.76
D.5.82
kN
kN
kN
kN
150. The condenser of a reheat power
plant rejects heat at the rate of 600 kW.
The mass flow rate of cooling water is 5
kg/sec and the inlet cooling water
temperature is 35°C. Calculate the
condenser cooling water exit temperature
43.45°C
B. 53.45°C
C. 63.66°C
D. 74.34°C
A.