Technological Institute of the Philippines
Mechanical Engineering Department
Pre-Board Examination
Monday, January 8, 2024
_
1. The cut off ratio of a diesel cycle is 1.12, the compression ratio is 10.3. Find the net work in
kJ/kg if the air entering the compression stroke is 17.8 °C
A. 45.02
B. 53.25
C. 54.02
D. 64.05
2. The cut-off ratio of a diesel cycle is 1.05 while the volume before and after compression is 3.3
m^3 and 0.25 m^3. What is its efficiency?
A. 45.02
B. 53.25
C. 54.02
D. 64.02
3. 60 kg/min of Air enters the compressor of a cold air standard brayton cycle at 104.43 kPa and
18.4 °C. The compression ratio of this cycle is 9.7 and the heat added is 227 kJ/s. Find the
maximum temperature of the cycle in °C. Cp = 1.0062 kJ/kg-K
A. 1004.4
B. 576.7
C. 675.7
D. 1040.4
4. Find the temperature in Centigrade of the compressor exit of an ideal brayton cycle in which the
lowest temperature is 19°C and the highest temperature is 973°C.
A. 330
B. 769
C. 876
D. 496
5. An ideal dual cycle takes in atmospheric air at 60°F. The cycle has a a pressure ratio of 2.2 ,
cut-off ratio of 1.5 and a compression ratio of 13.5. Find the heat rejected in Btu/lb (Cp =
0.24 BTU/lb-R and Cv=0.1714 BTU/lb-R
A. 330.5
B. 185.2
C. 256.6
D. 526.4
6. A carnot cycle compresses 6.10 kg/min of nitrogen gas using 37 kW of work. Find the pressure
ratio during compression if heat addition process occurs at a temperature of 771 °C.
A. 3.14
B. 4.18
C. 6.10
D. 8.11
7. The pressure ratio during compression of a standard otto cycle using hot air is 17.4. Find the
efficiency in %.
A. 55.79
B. 68.10
C. 57.6
D. 48.3
8. What should be the thickness of an 8” vertical pipe which has an elevation head of 100 feet. The
allowable stress is 3,000 psi.
A. 0.029
B. 0.058
C. 0.116
D. None of these
9. A thin hollow sphere has a thickness of 10 mm and a diameter of 150 mm. If the pressure inside
is the sphere is 5 MPa, what is the tangential stress on the sphere in psi?
A. 10,877.87
B. 2,719.47
C. 1,359.73
D. 5,438.93
10. A 2-in. solid shaft is driven by a 36-in. gear and transmits power at 120 rpm. If allowable
shearing stress is 12 ksi, what power can be transmitted?
A. 35.89 kW
B. 34.89 kW
C. 26.78 kW
D. 29.89 kW
11. A 1200 mm cast iron pulley is fastened to a 112.5 mm shaft by means of a 28.13 mm square key 175
mm long. What force in lbs acting at the pulley rim will shear the key if shear stress of the
key is 20.67 kg/mm2
A. 4,327.03
B. 21,030.49
C. 20,698.61
D. 9,539.37
12. The operation of cooling a heated piece of work rapidly by dipping it in water, brine or oil.
A. Annealing
B. Quenching
C. Normalizing
D. Tempering
13. A Fahrenheit and Celsius thermometer reading are equal in value. What would be the reading in
Kelvin?
A. -40
B. 233
C. 273
D. 420
14. A certain liquid boils at 20°C, what is the equivalent temperature in Réaumur scale?
A. 16
B. 293
C. 68
D. 12
15. The highest pressure drop in the refrigeration cycle occurs at the:
A. compressor
B. expansion valve C. evaporator
D. condenser
16. A vapor compression refrigeration system using R-22 has a capacity of 32 TOR. The low side and
high side temperatures are - 10°C and 40°C. Find the Heat rejected at the condenser in kJ/s.
@ -10°C hf = 188.40 kJ/kg hg=401.2 kJ/kg
@ 40°C hf= 249.65,
Compressor exit = h= 435.2 kJ/kg
A. 138
B. 183
C. 134
D. 143
17. 1500 kilograms Chicken (freezing point -5°C) initially at 18°C is delivered to a cold storage
every 6 hrs. Find the cooling load in tons of refrigeration if the storage temperature is 8°
below zero.
Cp above freezing: 3.18 kJ/kg-K,
Cp below freezing: 1.55 kJ/kg-K Latent Heat=246 kJ/kg
A. 3.4
B. 4.4
C. 5.4
D. 6.4
18. Find the heat radiated in Watts by a 4 cm x 4 cm hot plate with a temperature of 800°C.
A. 180.2
B. 360.4
C. 240.6
D. 120.3
19. Hot gases at 280°C flow on one side of a 10 mm thick plate and air at 35°C flows on the other
side. The heat transfer coefficient of the gases is 31.5 W/m2 -K and that of the air is 32 W/m2K.Find the over-all heat transfer coefficient if the value of thermal conductivity is 0.01 W/m-K
A. 230.48
B. 0.94
C. 15.82
D. 1.02
20. In a counter flow heat exchanger, the hot fluid enters at 500°F and exits at 320°F. The cooling
liquid enters at 120°F and leaves at 300°F. Find the LMTD in °F.
A. 200
B. 122
C. 180
D. None of these
21. The condenser of a steam power plant receives 1 kg/s of 100°C saturated steam. 10 L/s of Cooling
water enters the condenser at 20°C. If the condenser is a parallel flow heat exchanger, what is
the LMTD? @100°C hf=419.04 kJ/kg
hg= 2676.1 kJ/kg
Technological Institute of the Philippines
Mechanical Engineering Department
Pre-Board Examination
Monday, January 8, 2024
_
A. 48.11
B. 73.91
C. 100
D. None of these
22. In a A vertical furnace wall is made up of an inner wall of firebrick 20 cm thick followed by
insulating brick 15 cm thick and an outer wall of steel 1 cm thick. The surface temperature of
the wall adjacent to the combustion chamber is 1200°C while that of the outer surface of steel
is 50°C. The thermal conductivities of the wall material in W/m-K are firebrick, 10; insulating
brick, 0.26; and steel , 45. Neglecting the film resistances and contact resistance of joints,
determine the heat loss per 1.52 sq.m. of wall area.
A. 2.93
B. 1.93
C. 2.01
D. None of these
23. Find the efficiency in % of a brayton cycle using helium with an expansion ratio of 9.7
A. 20.93
B. 78.03
C. 40.8
D. 47.8
24. Find the work of the compressor in kW if the back work ratio is 0.09 (Wcompressor/Wturbine), the
heat added is 403 kW and the pressure ratio is 13.54 of a brayton cycle using cold air.
A. 20.93
B. 78.03
C. 40.8
D. 47.8
25. If the cp is 1.29769 kJ/kg K and the cv 0.73191 kJ/kg K. find the adiabatic ratio
A. 0.564
B. 1.399
C. 1.298
D. 1.773
26. What is the specific gas constant of CH56 in ft-lb / kg-K.
A. 90.16
B. 22.72
C. 0.122
D. 0.029
27. Which of these pipe colors is applicable for Fire Protection
A. Red
B. Blue
C. Green
D. Brown
28. Which of these pipe colors is applicable for High Pressure Air used in pneumatics
A. Red
B. Blue
C. Green
D. Brown
29. Find the time it takes a cool a 6 x 4 x 3 m room from 32°C to 22°C using an AC unit with a
tonnage of 7 TOR.
A. 325 sec
B. 34 min
C. 0.6 hrs
D. 5 mins
30. Find the volume of 2 kg of saturated air if the atmosphere is at 700 mmHg and 18°C. (@18°C
Psat=2.064 kPa).
A. 1.67
B. 1.79
C. 2.13
D. NONE OF THESE
31. 6 kg/hr of copra enters a drying chamber and leaves at 3.93 kg/hr Air at 101.325 kPa, 50°C db
10% RH is used to dry copra inside a drying chamber.
The Air leaves the drying chamber
saturated at 45°C db.Find the mass of air needed to absorb the moisture of copra
@50°C Psat=12.349 kPa @45°C Psat=9.593 kPa
A. 36.1
B. 42.2
C. 2.07
D. NONE OF THESE
32. Determine the amount of moisture in kg/hr removed/added to 3.6 kg/min of air at 95 kPa at 25°C
db 22°C wb to 22°C db and 80% RH.
@22°C Psat=2.645 kPa
@25°C Psat=3.169 kPa
A. 0.15 added
B. 0.15 removed
C. 0.51 added
D. 0.51 removed
33. Air at 33 C dry bulb and 18 C wet-bulb temperatures are cooled and humidified by passing it
through an air washer in which the water is continuously recirculated. The air leaves the air
washer at 23°C dry bulb temperature. What is the efficiency of the air washer in %?
A. 41.73
B. 52.15
C. 71.43
D. NONE OF THESE
34. Find the enthalpy of moist air at 25°C db and 18°C wb in kJ/kg.
@18°C Psat=2.064 kPa hg=2534.4 kJ/kg
@25°C Psat=3.169 kPa hg=2547.2 kJ/kg
A. 55
B. 45
C. 51
D. NONE OF THESE
35. A pump operating at 1750 rpm delivering 500 gpm against a total head of 112 ft. Changes in the
piping system have increased the total head to 343 feet. At what rpm should the pump be operated
at the new head
A. 3062.5
B. 1845.5
C. 2951.8
D. 965.5
36. For his Masters 8 tournament, Ash trains his Dragonite to fly using a blower supplying air
moving at 359 cubic feet per minute through a 1.09 x 2.19 ft duct under a pressure of 3 inches
water gage. The blower has a mechanical efficieny of 40% and electrical efficiency of 60%. Find
the Input Power in Watts
A. 84.40
B. 127.60
C. 30.38
D. 189.9
37. A fan has a total head of 276 meters of air and a static pressure of 19.88 cm wg. Find the
volume flow rate of air in m3/min of air through 1.84 x 0.58 meters of duct if the air density
is 1.458 kg/m3
A. 46
B. 76
C. 56
D. 66
38. An air compressor has a cylinder length of 12 cm and a stroke of 11.21 cm. Find the % clearance
A. 4.05
B. 6.58
C. 0.93
D. 7.05
39. Find the pressure at the 10th intercooler of an 18-stage screw compressor if the Pressure in kPa
at the 8th intercooler is 300 kPa and the discharge pressure is 8 MPa.
A. 578.5
B. 625.4
C. 874.2
D. 4444.4
40. What is the required base area of the foundation to support an engine with specified speed of
1323 rpm and the weight of 10,000 kg. Assume a safe bearing capacity of soil as 47,867 kPa. Use
c = .12
A. 20.5
B. 10.25
C. 8.87
D. 17.74
41. What height of wood is below water if its specific gravity is 0.65 and the height above the
water is 6.9 cm.
Technological Institute of the Philippines
Mechanical Engineering Department
Pre-Board Examination
Monday, January 8, 2024
_
A. 3 inch
B. 4 inch
C. 5 inch
D. 6 inch
42. What is the general solution for the differential equation 2y”-4y’+4=0
A. Acosx + Bsinx
B. e-x(Acosx+Bsinx) C. Aex+Be-x
D. ex(Acosx+Bsinx)
43. What is the distanced between A(1,1,1) and B(6,6,6)
A. 5√2
B. 6
C. 5√3
44. What is the value of the limit
A. 0
45. Find dy/dx if y= x^x
A. xx( ln|x|+1)
lim
𝑥→∞
D. 5
sin(5𝑥)
𝑥
B. 1
C. 5
D. 0.087
B. xx-1
C. xx
D. no derivative
46. Find the banking angle required in degrees for a section of a racetrack with a coefficient of
friction 0.15 and with racecars averaging at 200 mph and a radius of 2500 feet. The design is to
prevent the car skidding up the curve
A. 48.3
B. 55.4
C. 38.4
D. 46.9
47. For the pulley system shown, Find the weight of block W in Newtons.
A. 800
B. 923.76
C.
3200
D. 1600
48. A rich man deposits money at a bank with 1.83% interest compounded annually 19 years ago. After
that, he uses this money as his retirement fund, receiving 92,783.38 pesos monthly 168 times.
Find the amount of money he deposited.
A. PhP. 9,746,477.84
B. PhP.9,736,524.60 C. PhP. 3,421,652.51
D. None of these
49. Find the Interest gained of 4,532 pesos yearly payment with an interest of 8.99% for 18 years\
A. PhP. 186,993.48
B. PhP. 147,286.52 C.
PhP. 39,706.97
D. None of these
50. A radioactive material decays at a rate proportional to the amount. The amount after 5 years is
123 grams while the amount after 10 years is 100 grams. Find the original amount
A. 146.00
B. 186.52
C.
164.25
D. 151.29
51. Shannen was half as old as Iza was 5 years ago. Shannen is 2 yrs younger than Iza is now. Find
the Age of Iza
A. 2
B. 7
C.
9
D. 5
52. Find the eccentricity of a circle with x^2 + y^2 =25
A. 0
B. 2
C.
1
D. 0.134
53. A 150 mL 70% solution of alcohol is mixed with a 200 mL 60% solution of alcohol. What will be
the new concentration?
A. 42.00
B. 64.00
C.
130.0
D. 22.50
54. A 5 meter ladder initially has a 30° with the horizontal. If it slides 2 m/s to the left, at
what rate does it slide ,does is slide up or down.
A. 2.5 m/s down
B. 3.5 m/s up
C.
3.5 m/s down
D. 2.5 m/s up
55. Boiling water lowers down to 95°C after 5 mins inside a 25°C room . Find the temperature in °C
,20 mins after the water is inside the room.
A. 82
B. 55
C.
80
D. 57
56. What at what time after 8 pm will the hands of the clock meet.
A. 8:32
B. 8:40
C.
8:41
D. 8:43
57. Metals are conductive because:
A. The electrons are loosely bound to the nuclei and therefore mobile
B. Having characteristics luster
Technological Institute of the Philippines
Mechanical Engineering Department
Pre-Board Examination
Monday, January 8, 2024
_
C. They are on the left side of the periodic table
D. They have extra electrons as exhibited by normally possible balance state
58. Killed steel is always associated with:
A. Manganese
B. Silicon
C. Phosphorus
D. Sulphur
59. What is the different between brass and bronze?
A. Brass is composed of copper and zinc while bronze is composed of cooper and tin
B. Brass is composed of copper and zinc while bronze is basically copper and tin plus nonferrous alloy such as manganese, aluminium and chromium
C. Bronze is reddish in color while brass is a mixture of copper and antimony
D. Bronze is mostly an alloy of copper and tin while brass is a mixture of copper and antimony
60. It is recommended for high speed application that the minimum number of teeth in small sprocket
should be
A. 12 to 20
B. 18 to 24
C. 16 to 32
D. 14 to 28
61. A unit cell that contains nine atoms is known as the
A. Body centered cubic space lattice
B. Closed packed hexagonal space lattice
C. Face centered cubic space lattice
D. None of the above
62. Which medium has highest value of dielectric strength?
A. Glass
B. Mica
C. Porcelain
D. Quartz
63. An alloy of nickel and copper
A. Junel
B. Babbit
C. Monel
D. Kalel
64. An alloy of copper, tin, and antimony.
A. Inconel
B. Babbit
C. Monel
D. Kalel
65. Back rake angle for H.S.S. single point cutting tool to machine free cutting brass is:
A. 15°
B. 10°
C. 12°
D. 0°
66. The SAE recommends an angle of ________ for cone clutches faced with leather or asbestos or
having cork inserts.
A. 7.5°
B. 9.5°
C. 12.5°
D. 14.5°
67. The imperfection in the crystal structure of metal is known as:
A. Fracture
B. Dislocation
C. Slip
D. Crack
68. A wire rope that the wires and strands are twisted in opposite direction
A. Long lay
B. Lang lay
C. Regular lay
D. Wire Rope
69. The structure formed when transformation occurs at temperature down to the knee of the curve.
A. Pearlite
B. Bainite
C. Mythril
D. Limonite
70. Evaluate
𝜋/4
∫𝜋/10 𝑥𝑐𝑜𝑠(𝑥)𝑑𝑥
A. 0.214
B. 0.319
C.
0.259
D. -23.126
71. Find the area in square meters of a spherical lune cut from a 5 m radius sphere using an angle
of 0.14 radians.
A. 0.24
B. 7.00
C.
0.12
D. 12.0
72. Calculate the volume of a wedge which is cut at 18° from a sphere with a diameter of 20 meters
A. 209.4
B. 1675.5
C.
12,000
D. 628.3
73. Find the area of the shaded region in sq. centimeters if the chord tangent to the smaller circle
is 6 cm.
A. 144 pi
B. 9 pi
C. 12 pi
D. 36 pi
74. What polygon has 54 diagonals?
A. icosagon
B. decagon
C.
dodecagon
D. myriagon
75. By how much is the increase in volume of a cube if each edge is increased by 0.673%?
A. 4.03 %
B. 3.03 %
C. 2.03 %
D. 1.03 %
76. Find the area of a triangle with sides 39,25 and 40
A. 468
B. 486
C. 648
D. 864
77. Find the differential equation of a family of lines passing through (0,1)
A. (y-1)dy-xdy=0
B.(y-1)dx – xdy=0
C. xdy-ydx=0
D. ydy-xdy=1
78. The probability of getting at 2 heads when a fair coin is tossed four times is:
A. 11/16
B. 3/8
C. 1/4
D. 50%
Technological Institute of the Philippines
Mechanical Engineering Department
Pre-Board Examination
Monday, January 8, 2024
_
79. In a dice game,one fair dice is used, you get PhP. 7.00 when you roll a 4 or 6 and lose PhP.
5.00 when you roll any number. What would be the expected winning/losing amount?
A. 0
B. 10 gain
C. 10 loss
D. 1 loss
80. Find the area moment of inertia of a circle from the x if its diameter is 16 cm
A. 64π
B. 1024π
C. 16384π
D. 2048π
81. Determine the escape velocity in m/s on a planet whose radius is 6670km and mass is 5.98x10^24
kg.
A. 1234
B. 7733
C. 5588
D. 2977
82. The arithmetic mean of 100 numbers is 60, if two numbers 90 and 1500 is removed from the list,
what will be the new mean?
A. 45
B. 25
C. 44.1
D. 59
83. Mary is two times as old as Ann is now.Five years ago, she was three times as old as Ann was at
that time. How old is Ann now?
A. 12
B. 15
C. 10
D. 20
84. Three vectors A(5i+3j-2k), B(-2i+2j–2k) and C (3i-6j+k) intersect at a point. What is the
magnitude of the resultant?
A. 3.54
B. 8.76
C. 4.56
D. 6.78
85. What velocity must a rocket be fired so that it hits a tank that is 2.5 km away.
A. 222 m/s
B. 7 m/s
C. 156 m/s
D. 9.8 m/s
86. It is otherwise known as the Philippine Mechanical Engineering Act of 1998
A. RA 8459
B. RA 8495
C. RA 8594
D. RA 8945
87. What is the probability in % that you get a score of 70 or above from this exam just by
guessing?
A. 6.64 x 10-6
B. 1/4
C. 25
D. 4.37 x 10-19
88. Find the mode of the below data:
(1,5,1,6,8,1,6,8,5,3,3,2,7,4,1,7,9,5,8,8,9,7,2,8,6,2,5,4,9,2,5,4,3,8,1,5)
A. 5
B. 6
C. 7
D. 8
89. The process commonly used for thermoplastics is:
A. die-casting
B.injection molding C. shell molding
D. melt-molding
90. The effect of alloying zinc to copper is:
A. increase hardness
B. impart free machining properties
C. improve hardness and strength
D. to increase strength and ductility
91. What process is used in production of aluminum?
A. extrusion
B. case hardening
C. tempering
D. injection molding
92. What element is added to steel to improve machinability?
A. iron
B. carbon
C. sulfur
D. nickel
93. A steel tie rod on bridge must be made to withstand a pull of 500 lbs. Find the diameter of the
rod assuming a factor of safety of 2 and ultimate stress of 81,000 psf.
A. 0.71
B. 1.06
C. 2.08
D. 1.50
94. A steel pin on bridge must be made to withstand a torque of 500 lb-in. Find the diameter of the
rod assuming a factor of safety of 2 and ultimate stress of 81,000 psf.
A. 0.71
B. 1.06
C. 2.08
D. 1.50
95. A flange bolt coupling used on a pump consists of 10 bolts with 3/4" diameter each and 3” long.
The bolts reside on a 12” bolt circle. Calculate the allowable torque if the allowed stress is
6,000 psi
A. 13,253.59 lb-ft
B. 15,904.31 lb-ft C. 10,602.88 lb-ft
D. 14,506.55 lb-ft
96. The softening of metals by heat treatment and most commonly consists of heating the metals up to
near molten state and then cooling them very slowly.
A. Annealing
B. Quenching
C. Normalizing
D. Tempering
97. Reheating to a temperature below the transformation range, followed by any desired rate of
cooling to attain the desired properties of the metal.
A. Annealing
B. Quenching
C. Normalizing
D. Tempering
98. Heating to some above the transformation range with subsequent cooling to below that range in
still air at room temperature to produce uniform structure of the metal is termed as:
A. Annealing
B. Quenching
C. Normalizing
D. Tempering
99. The hardness of steel increase if it contains
A. Martensite
B. Austenite
C. Mercurite
D. Kryptonite
100.
Which of these is the lightest metal commonly alloyed with steel to make it lighter?
A. Lithium
B. Carbon
C. Nickel
D. Magnesium