Thermodynamics Past Paper PDF

Thermodynamics 1 1. If the pressure of a confined gas at a constant temperature is tripled, what will happen to the volume? a. The volume will be tripled b. The volume will be reduced to one-third of its original value* c. The volume will remain unchanged...

Thermodynamics 1 1. If the pressure of a confined gas at a constant temperature is tripled, what will happen to the volume? a. The volume will be tripled b. The volume will be reduced to one-third of its original value* c. The volume will remain unchanged d. The volume is constant. 2. The pressure of 750 mmHg in KN/m^2 a. 90 b. 100* c. 103 d. 110 3. The substance temperature was 620 degR. What is the temperature in degC? a. 50.7 b. 45.54 c. 71.11* d. 94.44 4. Unknown volume of container gas of gas of 1 atmosphere is allowed to expand to another container of 10 m^3 volume at 500 mm Hg at constant temperatures. Find the unknown volume. a. 6.58 m^3* b. 6.75 m^3 c. 5.67m^3 d. 7.65 m^3 5. An iron block weighs 5 Newton and has a volume of 200 cm^3. What is the density of the block? a. 2458 kg/m^3 b. 2485 kg/m^3 c. 2584 kg/m^3 d. 2549 kg/m^3* Thermodynamics 2 6. Determine the air-standard efficiency of an engine operating on the diesel cycle with clearance of 6% when the suction pressure is 99.87 kPa and the fuel is injected for 7% of the stroke. Assume k = 1.4. a. 62.11%* b. 51.2% c. 57.85% d. 60.23% 7. An otto cycle has a compression ratio of 8. Find the pressure during compression. a. 18.38* b. 16.38 c. 14.38 d. 12.38 8. 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 30C and 400C, of heat added to A is 1000 kW, find the work output of C. a. 549.78 kW b. 111.44 kW* c. 247.53 kW d. 141.89 kW 9. Air is compressed adiabatically from 30C to 100C. if mass of air being compressed is 5 kg. find the change in entropy. a. 1.039 kJ/K b. 0.746 kJ/K c.0* d. 1.245 kJ/K 10. A tank contains 90 ft3 of air at a pressure of 350 psig; if the air cooled until its pressure and temperature decreases to 200 psig and 70F respectively, what is the decrease in internal energy? a. 6232.09 Btu b. -5552.89 Btu c. 5552.89 Btu d. -6232.09 Btu* Heat Transfer 11. Which of the following is NOT a usual operation of the power/unit area Stefan-Boltzmann constant for black body radiation? a. 1.38 x 10-12 cal/ (sec cm2 K4) b. 5.68 x 10-5 ergs/ (sec cm2 K4) c. 5.68 x 105 watts/ (m2 K4) d. 5.68 x 10-8 coulombs/ (sec m2 K4) * 12. The heat loss/hr through 1 sq ft of furnace wall 18 inches thick is 520 BTU. The inside wall temp is 1900F and its average thermal conductivity is 0.61 BTU/hr ftF. The outside surface temperature of the wall is nearest to: a. 100F b. 300F c. 600F * d. 1000F 13. 55,000 gallons of water passes through a heat exchanger and absorbs 28,000,000 BTU’s. The exit temperature is 110F. The entrance water temperature in F is nearest to: a. 49* b. 56 c. 68 d. 73 14. The temperature difference between the two sides of a solid rectangular slab of area A and thickness L as shown below is ∆T. The heat transferred through the slab by conduction in time T is proportional to: a. AL∆Tt b. AL (∆T/t) c. AL (t/∆T) d. A∆Tt/L * 15. A vertical furnace wall is made up of an inner wall of firebrick 20cm 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 degC while that of the outer surface of steel is 50 degC. 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 sq.m. of wall area. a. 1.93 W/m2* b. 2.93 W/m2 c. 1.55 W/m2 d. 2.55 W/m2 Combustion  16. A cylindrical tank 4m long and 3m diameter is used for oil storage. How many days can the tank supply the engine having 27oAPI with fuel consumption of 60kg/hr? a. 17.53* b. 5.84 c. 12.84 d. 19.84 17. 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 2900KW-hrs. Industrial fuel used is 30oAPI and was purchased at P30.00/li at 60oF. Determine the overall thermal efficiency of the plant. a. 26.08% b. 34.23% c. 28.00%* d. 18.46% 18. The dry exhaust gas from oil engine has the following gravimetric analysis: CO2 = 21.6%; O2 = 4.2%; N2 = 74.2% Specific heats at constant pressure for each component of the exhaust gas in Kcal/kgoC are: CO2 = 0.203; O2 = 0.219; N2 = 0.248 Calculate the specific gravity if the molecular weight of air is 28.97 kg/kg-mol. a. 0.981 b.1.244 c. 1.055* d.0.542 19. 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. a. 2.870 b. 7.526* c. 2.274 d. 6.233 20. 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 ratio for complete combustion of molal basis. a. 2.130 b. 3.230 c. 1.233* d. 1.130 Fluid Mechanics 21. Find the pressure at the 100-fathom depth of water in kpag. a. 1,793.96 kpag* b. 1,893.96 kpag c. 1,993.96 kpag d. 1,693.96 kpag 22. Find the depth in furlong of the ocean (SG = 1.03) if the pressure at the seabed is 2,032.56 kpag. a. 1* b. 2 c. 3 d. 4 23. The barometer of a mountain hiker reads 930 mbars at the beginning of a hiking trip and 780 mbars at the end. Neglecting the effect of altitude on local gravitational acceleration, determine the vertical distance climb. Assume g = 9.7 m/s2. a. 1275.21 m b. 1289.00 m* c. 1267.34 m d. 1583.34 m 24. The lower half of a 10 m high cylindrical container is filled with water and the upper half with oil that has SG = 8.85. Determine the pressure difference between the top and bottom of the cylinder. a. 90.74 Kpa* b. 92.74 Kpa c. 83.38 Kpa d. 98.10 Kpa 25. What is the static head corresponding to a flow velocity of 10 ft/sec? a. 1.55 ft* b. 1.75 ft c. 2.05 ft d. 2.25 ft Refrigeration and Air Conditioning 26. At 35% solution leaves the absorber and 30% solution enters the absorber. The heat removed from the absorber by cooling water is 547.6 Btu and ammonia is superheated by 10°. Find the pound per pound of ammonia gas from the evaporating coils. a. 11 b. 12 c. 13* d. 14 27. 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 room for a mass of 4 lbs refrigerant. a. 200* b. 210 c. 220 d. 230 28. Compute the free-aperture cross section in m2 for the ventilation of a machinery room if the mass of refrigerant is 9 kg. a. 0.314 b. 0.414* c. 0.514 d. 0.614 29. A 29.53” x 39.37” pressure vessel contains ammonia with f = 0.041. Compute the minimum required discharge capacity of the relief device in kg/hr. a. 106.71 kg/hr b. 108.71 kg/hr c. 110.71 kg/hr* d. 112.71 kg/hr 30. Saturated vapor ammonia at -16OC (h1 = 1442.60 kJ/kg) leaves the evaporator and enters the compressor at -6OC (h1 = 1465kJ/kg. The refrigerant leaves the condenser as saturated liquid at 40OC (h4= 390.6 kJ/kg) and enters the expansion valve at 35OC (h5 =366.1kJ/kg). Heat rejected from the compressor amount to 50kW. The work to compressor is 208kJ/kg, while the heat loss from  compressor is 33kJ/kg. If 95kJ/kg of heat are lost in the piping between the compressor discharge and condenser inlet, determine the refrigerating capacity of the system. a. 49.5 TR b. 46.61 TR c. 12.88 TR d. 13.24 TR* 31. A room contains air at 20C and 96 kPA at a relative humidity of 75%. Determine the enthalpy of moist air. a. 45.919 KJ/kgda b. 45.515 KJ/kgda c. 49.515 KJ/kgda* d. 41.815 KJ/kgda 32. Determine the mass of water vapour contained in a 150m3 room at 100 kPa, 23C and 40% relative humidity. From steam tables: Psat @ 23C=2.810 kPA. a. 1.6342 kg b. 1.9342 kg c. 1.2342 kg* d. 2.2342 kg 33. A 5 m x 4 m x 4 m room has an air temperature of 32 oC (psat = 4.559 kPaa, hg = 2559.9 kJ/kg) and the pressure is 101 kPaa. The mass of water vapor in air is 2.5 kg with Rv = 0.45 kJ/kg-oK. What is the relative humidity of the air? a. 94.08 %* b. 74.08 % c. 84.08 % d. 64.08 % 34. An air-vapor mixture has a dry bulb temperature of 30 oC and a humidity ratio of 0.015 kg/kg d.a., calculate the enthalpy of the moist air. a. 68.527 kJ/kg d.a* b. 86.527 kJ/kg d.a. c. 65.827 kJ/kg d.a. d. 67.528 kJ/kg d.a 35. The approach and efficiency of cooling tower are 10 oC and 65 %, respectively. If the temperature of water leaving the tower is 27 oC, determine the temperature of water entering the tower. a. 54.57 oC b. 55.47 oC c. 45.57 oC* d. 54.75 oC 36. The refrigerating effect of 100 tons refrigeration is 117 KJ/kg. Determine the mass flow of refrigerant. a. 1kg/sec b. 2kg/sec c. 3 kg/sec* d. 4 kg/sec 37. A rectangular duct has a dimension of 0.25 m by 2 m. determine the equivalent diameter of the duct. a. 0.50 m b. 0.60 m c. 0.70 m d. 0.40 m* 38. Determine the heat extracted from 2000 kg of water from 25C to ice at -10C. a. 621,150 kJ b. 821,150 kJ c. 921,150 kJ* d. 764,917 kJ 39. A refrigeration system is used to cool water in the evaporator a 8 kg/s of water from 30C to 2C. Find the tons of performance required. a. 136.75 TOR b. 139.45 TOR c. 121.35 TOR d. 266.75 TOR* 40. Find the sensible heat factor of an air-conditioning unit having a sensible heat load of 90 kW and latent heat load of 40 kW. a. 65.50% b. 67.35% c. 69.23%* d. 71.45% 41. Re-circulated air of 10 kg/s with 53 KJ/kg dry air enthalpy and outside air of 4 kg/s with 90KJ/kg dry air enthalpy enters the conditioning unit. Determine the air conditioning capacity of air conditioning apparatus if the supply enthalpy to conditioned space is 42 kJ/kg dry air. a. 184 KW b. 204 KW* c. 302 KW d. 154 KW 42. Thirty kilogram of cooling tower per second enters the condenser 25˚C and leaves at 50˚C. Find the heat carried away by water. a. 3140.25 kW* b. 4231.68 kW c. 2555.55 kW d. 2879.90 kW 43. Copra enters a dryer containing 70% moisture and leaves at 7% moisture. Find the moisture removed on each pound of solid in the final product. a. 5.558 lb b. 2.258 lb* c. 4.458 lb d. 3.358 lb 44. A classroom that normally contains 40 people is to be air- conditioner with window air-conditioning units of 5 KW cooling capacity. A person at rest may be assumed to dissipate heat at a rate of about 360 KJ/hr. There are 10 light bulbs in the room, each with a rating of 100 watts. The rate of heat transfer to the classroom through the walls and the windows is estimated to be 15,00 KJ/hr. If the room air is to be maintained at a constant temperature of 21oC, determine the number of window air- conditioning units required. a. 1 unit b. 2 units * c. 3 units d. 4 units 45. A 4m x 5m x 6m room is to be heated by a baseboard resistance heater. It is desired that the resistance heater be able to raise the air temperature in the room from 7 to 23oC within 15 minutes. Assuming no heat losses from the room and an atmospheric pressure of 100 kpa, determine the required power of the resistance heater. Assume constant specific heats at room temperature. a. 2.34 KW b. 1.91 KW* c. 4.56 KW d. 6.34 KW  46. A student in a 4m x 6m x 6m dormitory room turns on her 150 watts fan before she leaves the room on a summer day, hoping that the room will be cooler when she comes back in the evening. Assuming all the doors and windows are tightly closed and disregarding any heat transfer through the walls and the windows, determine the temperature in the room when she comes back 10 hours later. Use specific heat values at room temperature, and assume the room to be at 100 kpa and 15oC in the morning when she leaves a. 28.13oC b. 38.13oC c. 48.13oC d. 58.13oC* 47. An air-conditioning system is used to maintain a house at 75OF when the temperature outside is 95OF. The house is gaining heat through the walls and windows at a rate of 1250 Btu/min, and the heat generation rate within the house from people, lights and appliances amounts to 350 Btu/min. Determine the minimum power input required for this air-conditioning system. a. 10.06 hp b. 1.36 hp c. 1.41 hp* d. 7.94 hp 48. An auditorium seating 1500 people is to be maintained at 80℉ dry bulb and 85℉ wet bulb temperature when outdoor air is at 91℉ dry bulb and 75℉ wet bulb. Solar heat load is 110,000 Btu/hr and supply air at 60℉, determine the amount of supply air. a. 93,229.17 lb/hr* c. 83,229.17 lb/hr b. 73,229.17 lb/hr d. 63,229.17 lb/hr 49. A room contains air at 20C and 96 kPA at a relative humidity of 75%. Determine the enthalpy of moist air. a. 45.919 KJ/kgda c. 45.515 KJ/kgda b. 49.515 KJ/kgda* d. 41.815 KJ/kgda 50. Determine the mass of water vapor contained in a 150m3 room at 100 kPa, 23C and 40% relative humidity. From steam tables: Psat @ 23C=2.810 kPA. a. 1.6342 kg b. 1.9342 kg c. 1.2342 kg* d. 2.2342 kg Industrial Plant Engineering 51. A water tube boiler has a capacity of 1000 kg/hr of steam. The factor of evaporation is 1.3 boiler rating is 200%, boiler efficiency is 65% heating surface area is 0.91 m^3 per bo.Hp, and the heating value of fuel is 18,400 Kcal/kg. the total coal available in the bunker is 50,000 kg. Determine the no, of hrs to consume the available fuel. a. 853.36 hrs* b. 706.57 hrs c. 979.46 hrs d. 100.75 hrs 52. Two boilers are operating steadily on 91,000 kg of coal contained in a bunker. One boiler is producing 1591 kg of steam per hour at 1.2 factor of evaporation and an efficiency of 65% and another boiler produced 1364 kg of steam per hour and 1.15 factor of evaporation and an efficiency of 60%. How many hours will the coal in the bunker run the boiler if the heating value of the coal is 7,590 Kcal/kg? a. 230.80 hrs* b. 280.54 hrs c. 350.35 hrs d. 300.54 hrs 53. The heating value of fuel supplied in a boiler is 40,000 kj/kg. if the factor of evaporation is 1.10 and the actual specific evaporation is 10, what is the efficiency of the boiler? a. 62.70%* b. 53.08 % c. 78.05 % d. 54.97 % 54. What is the rate of evaporation of a water tube boiler if the factor of evaporation is 1.10, percent rating of 200% and the heating surface area is 250 m^2? a. 7,817.16 kg/hr* b. 7,898.67 kg/hr c. 6,789.45 kg/hr d. 5,768.54 kg/hr 55. A boiler plant generates 224,000 lb of steam and burns 13.9 tons of coal per hour. The coal has a heating value of 11400 BTU/lb. A test of particulates leaving the boiler shows that 3804 lb of particulate is being discharged per hour. What is the particulate discharged per million BTU heat input to the furnace? a. 12 lb/106 BTU * b. 14 lb/106 BTU c. 15 lb/106 BTU d. 16 lb/106 BTU 56. The gas density of chimney is 0.75 kg/m^3 and air density of 1.15 kg/m^3. If the driving pressure is 0.25 kPa, determine the height of the chimney. a. 54.6 m b. 63.7 m * c. 74.6 m d. 68.5 m 57. The actual velocity of gas entering in a chimney is 8 m/sec. The gas temperature is 25 deg C and pressure of 98 kPa with a gas constant of 0.287 kJ/kg-K. Determine the chimney diameter if mass of gas is 50,000 kg/hr. a. 1.57 m b. 1.81 m q c. 3.56 m d. 1.39 m* 58. A coal fired steam boiler uses 3000 kg of coal per hour. Air required for combustion is 15.5 kg per kg of coal at barometric pressure of 98.2 kPa. The flue gas has temperature of 285 deg C and an average molecular weight of 30. Assuming an ash loss of 11% and allowable gas velocity of 7.5 m/sec, find the diameter of chimney. a. 1.91 m * b. 1.82 m c. 2.62 m d. 2.93 m 59. A power plant situated at an altitude having an ambient air of 96.53 kPa and 23.88 deg C. Flue gases at a rate of 5.0 kg/sec enter the stack at 200 deg C and leaves at 160 deg C. The flue gases gravimetric analysis are 18% CO2, 7% O2 and 75% N2. Calculate the diameter of stack in meters for driving pressure of 0.20 kPa. a. 0.75 b. 0.85 c. 0.95* d. 1.15 60. A 10-stages air compressor compresses air from 100 kpa to 800 kpa. Find the intercooler pressure between 1 st and 2nd stage. a. 282.84 kpa b. 113.21 kpa c. 123.11 kpa* d. 333.51 kpa 61. A 3-stages air compressor compresses air from 100 kpa to 700 kpa. Find the intercooler pressure between the 2 nd and 3rd stage. a. 365.88 kpa* b. 375.88 kpa c. 385.88 kpa d. 395.88 kpa 62. The discharge pressure of an air compressor is 5 times the suction pressure. If volume flow at suction is 0.1 m3/sec, what is the suction pressure if compressor work is 19.57 kw? (Use n=1.35) a. 97 kpa b. 98 kpa* c. 99 kpa d. 100 kpa 63. A diesel electric plant supplies energy for Meralco. During a 24-hour period, the plant consumed 240 gallons of fuel at 28°C and produced 3930 KW-hr. Industrial fuel used is 28°API and was purchased at P30 per liter at 15.6°C. What is the cost of the fuel be to produce one KW-hr? a. P6.87* b. P1.10 c. P41.07 d. P5.00 64. A turbo-charged, 16-cylinder, Vee-type diesel engine has an air consumption of 3,000 kg/hr per cylinder at rate load and speed. This air is drawn in through a filter by a centrifugal compressor directly connected to the exhaust gas turine. The temperature of the air from the compressor is 135C and a counter flow air cooler reduces the air temperature to 45C before it goes to the engine suction heater. Cooling water enters air cooler at 30C and leaves at 40C. Calculate the log mean temperature difference. a. 47.23C b. 87.82C c. 43.34C* d. 65.24C 65. The charge in a Diesel engine consists of 18.34 grams of fuel, with lower heating value of 42,571 KJ/kg, and 409 grams of fuel and products of combustion. At the beginning of compression, t1 = 60℃. Let rk = 14. For constant cP = 1.11 KJ/kg-C, what should be the cut-off ratio in the corresponding ideal cycle? a. 2.05 b. 2.34 c. 5.34 d. 2.97* 66. A 650 BHP diesel engine uses fuel oil of 280API gravity, fuel consumption is 0.65 lb/BHP-hr. Cost of fuel is P 7.95 per liter. For continuous operation, determine the minimum volume of cubical day tank in cm3, ambient temperature is 450C. a. 4,372,890 cm3 b. 5,987,909 cm3 c. 5,291,880 cm3 * d. 7,352,789 cm3 67. The total head of fan is 187m and has a static pressure of 210mm of water gage, what is the velocity of air flowing if density of air is 1.15 kg/m^3 ? a. 6.85 m/sec b. 3.45 m/sec c. 4.39 m/sec d. 9.28 m/sec* 68. A fan delivers 5.7 m^3/sec. at a static pressure of 5.08 cm of water when operating at a speed of 400rpm. The power input required is 2.963 KW. If 7.05 m^3/sec. are desired in the same fan and installation, find the pressure in cm of water. a. 7.77* b. 17.14 c. 11.43 d. 5.08 69. Calculate the air power of a fan that delivers 1200m3/min of air through a 1m x 1.5m outlet. Static pressure is 120mm WG and density of air is 1.18. a. 20.45 HP b. 25.64 HP* c. 30.45 HP d.35.64 HP 70. In air standard brayton cycle, the inlet temperature and pressure are 20C and 101.325kPa. The turbine inlet condition is 1200 kPa and 900C. Det the air flow rate if the turbine produces 12 MW. a. 21.41 kg/s b. 20.20 kg/s * c. 19.25 kg/s d. 18.10 kg/s 71. A gas turbine power plant operating on the Brayton cycle delivers 15 MW to a standby electric generator. What is the mass flow rate and the volume flow rate of air if the minimum and maximum pressures are 100 kPa and 500 kPa respectively, and temperature of 20C and 1000C. a. 31.97 kg/s, 26.88 m3/s * b. 36.98 kg/s, 28.99 m3/s c. 41.97 kg/s, 26.88 m3/s d. 46.98 kg/s 28.99 m3/s 72. In an ideal standard Brayton cycle, 1.5 kg/s of air at 101 kPaa and 27 oC is compressed isentropically to a certain pressure and temperature after which the is added until the temperature becomes 1027 oC. Isentropic expansion occurs in the turbine. Determine the net power produced by the cycle. a. 629.56 kW b. 592.65 kW c. 529.76 kW* d. 579.26 kW 73. In a 12 MW geothermal power plant, the mass flow of steam entering the turbine is 26 kg/sec. The quality after throttling is 25% and enthalpy of ground water is 750 kJ/kg. Determine the overall efficiency of the plant.  a. 7.4 % b. 9.6 % c. 5.4 % d. 15.4 % 74. A 16,000KW 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 200, 000 kg/hr, determine the number of wells are required to produce if the charge of enthalpy if the change of enthalpy at entrance and exit of turbine is 500KJ/kg. a. 4 wells* b. 2 wells c. 6 wells d. 8 wells 75. A Pelton type turbine has 25 m head friction loss of 4.5 m. The coefficient of friction head loss (from Moorse) is 0.00093 and penstock length of 80 m. What is the penstock diameter? a. 1,355.73 mm* b. 3,476.12 mm c. 6771.23 mm d. 1686.73 mm 76. In an 9,000 KW hydro-electric plant the overall efficiency is 88% and the actual power received by the customer is 110,000 KW-hrs for that day. What is the secondary power could this plant deliver during the entire day? a. 58,960 KW-hrs b. 80,080 KW-hrs* c. 65,960 KW-hrs d. 70,960 KW-hrs 77. A Pelton type turbine was installed 30 m below the gate of the penstock. The head loss due to friction is 12 percent of the given elevation. The length of penstock is 100 m and coefficient of friction is 0.00093. Determine the power output in KW. (Use Moorse equation) a. 22,273 b. 23,234 c. 32,345 d. 34,452* 78. How many identical turbines, operating at 139.0 rpm at 191% efficiency (specific speed = 5.4), are needed to exploit a head of 1200 ft and a flow of 1660 ft/s. a. 2 turbines b. 3 turbines* c. 4 turbines d. 5 turbines 79. Cascade refrigeration cycle is often used in industrial processes where objects must be cooled to temperature below. a. -46C* b. -56C c. -65C d. -76C 80. Type of refrigerant control designed to a pressure difference while the compressor is operating. a. Thermostatic expansion valve c. Using low side float flooded system b. Automatic expansion valve d. Capillary tube* 81. As a rule of thumb, for a specified amount of compressed air, the power consumption of the compressor decreased by_________ for each 3C drop in the temperature inlet air to the compressor. a. 1%* b. 1.5% c. 2% d. 2.5% 82. Modern way of detecting air compressor leak is by: a. Soup and water c. Air leak detector b. Acoustic leak detector* d. Ammonia leak detector 83. For foundation of stacks, the maximum pressure on the soil is equal to the pressure due to weight and the ________. a. Soil movement b. Wind movement* c. Ground movement d. Engine movement 84. Foundation bolts of specified size should be used and surrounded by a pipe sleeve with an inside diameter of at least. a. 3 times the diameter of engine bolt c. 2 times the diameter of engine bolt b. 3 times the diameter of anchor bolt * d. 2 times the diameter of anchor bolt 85. For multistage compression of an ideal Brayton cycle, the back work ratio will: a. Increase b. decrease* c. remains the same d. none of these 86. A submersible pump delivers 350 gpm of water to a height of 5 ft from the ground. The pump was installed 150 ft below the ground level and draw down of 8 ft during the operation. If water level is 25 ft above the pump, determine the pump power. a. 7.13 KW b. 4.86 KW c. 7.24 KW d. 9.27 KW* 87. A vacuum pump is used to drain a flooded mine shaft of 20℃ water. The pump pressure of water at this temperature is 2.34 KPa. The pump is incapable of lifting the water higher than 16 m. What is the atmospheric pressure? a. 159.30* b. 32.33 c. 196.22 d. 171.9 88. A submersible, multi-stage, centrifugal deep well pump 260 gpm capacity is installed in a well 27 feet below the static water level and running at 3000 rpm. Drawdown when pumping at rated capacity is 10 feet. The pump delivers the water into a 25,000 gallons capacity overhead storage tank. Total discharge head developed by pump, including friction in piping is 243 feet. Calculate the diameter of the impeller of this pump in inches if each impeller diameter developed a head of 38 ft. a. 3.28 b. 5.33 c. 3.71* d. 6.34 89. Steam is admitted to the cylinder of an engine in such manner the average pressure is 120 psi. The diameter of the piston is 10 in. and the length of stroke is 12 in. What is the Hp of the engine when it is making 300 rpm? a. 171.4 Hp* b. 175 Hp c. 173.2 Hp d. 174 Hp 90. During the working stroke of an engine the heat transferred out of the system was 150 KJ/kg of working substance. The internal energy also decreased by 400 kJ/kg of working substance. Determine the work done. a. 250 kJ/kg * b. 550 kJ/kg c. 600 kJ/kg d. 350 kJ/kg 91. A heat engine has a thermal efficiency of 50%. How much power does the engine produce when heat is transferred at a rate of 10^6 kJ/hr? a. 50 MW b. 75 MW c. 138 MW * d. 147 MW 92. A steam engine operating between a boiler temperature of 220degC and a condenser temperature of 35degC delivers 8 Hp. If its efficiency is 30 percent of that for a Carnot engine operating between this temperature limits, how many calories are absorbed each second by the boiler? a. 12.7 kCal/s* b. 11.34 kCal/s c. 10.56 kCal/s d. 9.57 kCal/s 93. Determine the indicated mean effective pressure of an engine, in psi, having a brake mean effective pressure of 750 kPa and 80 % mechanical efficiency. a. 138 b. 137 c. 136* d. 135 94. Determine the diameter of the stud bolt that are required to fasten down the cylinder head of a 203 mm x 304 mm gas engine. There are ten bolts on the block. The explosion pressure is 31 kg/sq.cm and studs are made of ordinary bolts material SAE 1020. How deep should the bolt be drilled? a. 38.1 mm* b. 40.2 mm c. 37.3 mm d. 35.5 mm 95. A single threaded trapezoidal metric thread has a pitch of 4 mm, and a mean diameter of 18 mm. It is used as a translation screw in conjunction with a collar having an outside diameter of 37 mm and an inside diameter of 27 mm. Find the required torque in N-m to raise a load of 400 kg if the coefficient of friction is 0.3 for both thread and collar. a. 34.6 N-m b. 32.6 N-m* c. 39.1 N-m d. 38.5 N-m 96. A single square thread power screw is to raise a load of 70 kN. The screw has a major diameter of 36 mm and a pitch of 6 mm. The coefficient of thread friction and collar friction are 0.13 and 0.10 respectively. If the collar mean diameter is 90 mm and the screw turns at 60rpm, find the combined efficiency of screw and collar. a. 13.438% b. 15.530% c. 14.526% d. 12.526%* 97. Entrance losses between tank and pipe or losses through elbows, fittings and valve are generally expresses as a function of; a. Kinetic energy* b. pipe diameter c. friction factor d. volume flow rate 98. The air that contains no water vapor is called. a. Zero air b. saturated air c. dry air* d. humid air 99. In psychometric chart, that constant-enthalpy lines coincide with constant-temperature lines at temperature. a. Above 50C b. below 40C c. below 50C* d. above 10C 100. Air motion also plays important role in. a. Surroundings b. cooling c. human comfort* d. none of these