401-499

418. During takeoff in a spaceship, an astronaut is subjected to acceleration equal to 5 times the pull of the earth's standard gravity. If the astronaut is 180 lbm and the takeoff is vertical, what force does he exert on the seat? A. 4810.9 N B. 4414.5 N C. 8829 N D. 9620 N

A. 4810.9 N

460. Compute the humidity ratio of air at 70% relative humidity and 25°C when the barometric pressure is 101.325 kPa. From the steam tables: Psat @ 34 °C = 3.169 kPa. A. 0.014 kgwater vapor/kgdry air C. 1.4 kgwater vapor/kgdry air B. 0.14 kgwater vapor/kgdry air D. 0.0014 kgwater vapor/kgdry air

A. 0.014 kgwater vapor/kgdry air

479. A condenser vacuum gauge reads 600 mm Hg when the barometer reads 760 mm Hg. What is the absolute condenser pressure in bar? A. 0.0213 B. 0.061 C. 0.213 D. 0.610

A. 0.0213

419. A pressure cooker operates by cooking food at a higher pressure and temperature possible at atmospheric conditions. Steam is contained in the sealed pot, with vent hole in the middle of the cover, allowing steam to escape. The pressure is regulated by covering the vent hole with a small weight, which is displaced slightly by escaping steam. Atmospheric pressure is 100 kPa, the vent hole area is 7-mm2, and the pressure inside should be 250 kPa. What is the mass of the weight? A. 0.107 kg B. 1.05 kg C. 1.75 kg D. 0.1783 kg

A. 0.107 kg

402. A hydro-electric impulse turbine is directly coupled to a 24 pole, 60 Hz alternator. It has a specific speed of 60 rpm and develops 3000 Hp. What is the required diameter assuming a peripheral speed ratio of 0.45? A. 0.661 m B. 0.552 m C. 0.443 m D. 0.773 m

A. 0.661 m

451. Specific volume is the number of cubic meters of mixture per kilogram of dry air. If dry air has these following properties: Ra = 287 J/kg-K, T = 303 K, Pa = 99.604 kPa. Solve for the specific volume. A. 0.873 m3/kg B. 0.853 m3/kg C. 0.953 m3/kg D. 0.783 m3/kg

A. 0.873 m3/kg

412. A two-stage air compressor at 90 kPa and 20°C discharges at 700 kPa. Find the polytropic exponent n if the intercooler intake temperature is 100°C. A. 1.29 B. 1.33 C. 1.4 D. 1.25

A. 1.29

459. The thermal efficiency of a Carnot cycle operating between 170°C and 620°C is closest to: A. 44% B. 50% C. 63% D. 73%

B. 50%

432. A boiler plant generates 225,000 lb of steam and burns 13.9 tons of coal per hour. The coal has a heating value of 11,400 Btu/lb. A test of the 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

A. 12 lb/106 Btu

446. During the experiment on Charles Law, the volume of the gas trapped in the apparatus is 10000 mm³ when the temperature is 18°C. The temperature of the gas was then raised to 85°C. Determine the new volume of the gas trapped in the apparatus if the pressure exerted on the gas remained constant. A. 12302.41 mm³ B. 8128.49 mm³ C. 70833.33 mm³ D. 2117.64 mm³

A. 12302.41 mm³

422. A mixture of 0.4 lbm of helium and 0.2 lbm of oxygen is compressed polytropically from 14.7 psia and 60oF t0 60 psia according to n = 1.4. Determine the polytropic work. A. 139 Btu B. 239 Btu C. 339 Btu D. 539 Btu

A. 139 Btu

405. In a hydro-electric plant, water flows at 10 m/s in a penstock of 1 m3 cross-sectional area. If the net head of the plant is 30 m and the turbine efficiency is 85%, what is the turbine output? A. 2,501.55 kW B. 2,100.21 kW C. 3,626.34 kW D. 3,124.65 kW

A. 2,501.55 kW

481. What is the resulting pressure when one kilogram of air at 104 kPa and 98°C is heated at constant volume to 450°C? A. 202.67 kPa B. 194.67 kPa C. 186.53 kPa D. 198.65 kPa

A. 202.67 kPa

406. A 75 MW power plant has an average load of 35,000 kW and a load factor of 65%. Find the reserve over peak. A. 21.15 MW B. 23.41 MW C. 25.38 MW D. 18.75 MW

A. 21.15 MW

445. 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

A. 250 kJ/kg

471. An Otto cycle has an initial pressure of 100 kPa and has a pressure of 400 kPa after adiabatic compression. Find the cycle efficiency. A. 32.70% B. 34.70% C. 36.70% D. 38.70%

A. 32.70%

453. At a pressure of 60°F, a motorbike Ire is inflated to 33 psig. As it is driven along the C -5 road, the temperature rose to 76°F. Assuming the volume remains constant, determine the final gauge pressure. Given: P1 = 33 psig + 14.7 psig = 47.7 psig T1 = 60°F + 460 = 520°R T2 = 76°F + 460 = 536°R A. 34.47 psig B. 49.17 psig C. 35.00 psig D. 34.30 psig

A. 34.47 psig

434. Find the thrust and efficiency of two 2-m diameter propellers through which flows a total of 600 m3/s of air to 11.3 N/m3. The propellers are attached to an airplane moving at 250 kph through still air. Neglect eddy losses. A. 36,077 N, 73% B. 77,630 N, 37% C. 66,033 N, 33% D. 77,330 N, 77%

A. 36,077 N, 73%

458. A car engine with a power output of 65 hp has a thermal efficiency of 24%. Determine the fuel consumption rate of this car if the fuel has a heating value of 19,000 Btu/lbm. A. 36.28 lbm/hr B. 37.28 lbm/hr C. 37.28 lbm/hr D. 35.30 lbm/hr

A. 36.28 lbm/hr

409. Calculate the use factor of a power plant if the capacity factor is 35% and it operates 8000 hrs during the year? A. 38.325% B. 33.825% C. 35.823% D. 32.538%

A. 38.325%

476. Determine the pressure exerted on a diver at 30 m below the free surface of the sea. Assume a barometric pressure of 101 kPa and the specific gravity of sea water is 1.03. A. 404 kPa B. 410 kPa C. 420 kPa D. 430 kPa

A. 404 kPa

484. A Carnot cycle operates between 30°C and 350°C. Find the cycle efficiency. A. 51.36% B. 63.45% C. 45.37% D. 76.45%

A. 51.36%

433. A turbine receives 150 lbm/s of air at 63 psia and 2450°R and expands it polytropically to 14.7 psia. The exponent n is equal to 1.45 for the process. Determine the power. A. 52,343.16 BTU/s C. 53.343.16 HP B. 52,343.16 kW D. 53,343.16 ft-lb/s

A. 52,343.16 BTU/s

404. The tailwater and headwater of a hydro-electric plant are 150 m and 200 m respectively. What is the water power if the flow is 15 m3/s and a head loss of 10% of the gross head? A. 6,621.75 kW B. 7,621.65 kW C. 5,621.76 kW D. 4,621.56 kW

A. 6,621.75 kW

438. A pump discharges 550 gpm of water to a height of 35 ft. With an efficiency of 80%, what is the power input? A. 6.09 hp B. 6.32 hp C. 4.74 hp D. 4.94 hp

A. 6.09 hp

494. 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? A. 600 kJ B. 900 kJ C. 300 kJ D. 1,200 kJ

A. 600 kJ

413. A two-stage compressor receives 0.35 kg/s of air at 100 kPa and 269 K and delivers it at 5000 kPa. Find the heat transferred in the intercooler. A. 70.49 kW B. 80.49 kW C. 90.49 kW D. 100.49 kW

A. 70.49 kW

455. Aluminum has a specific heat of 0.902 J/g-°C. How much heat is lost when a piece of aluminum with a mass of 23.984 g cools from a temperature of 415.0°C to a temperature of 22.0°C? A. 8500 J B. 6000 J C. 80000 J D. 7500 J

A. 8500 J

456. If the temperature of an air parcel is -20.5°C, and its density is 0.690 kg/m3, what is the pressure of the air parcel? A. 40 kPa B. 50 kPa C. 60 kPa D. 70 kPa

B. 50 kPa

436. A reciprocating compressor handles 1,400 cfm of air measured at intake where P1 = 18 psia and T1 = 90°F. The discharge pressure is 92 psia. Calculate the work if the process of the compression is isothermal. A. -180.5 hp B. -179.5 hp C. -227.6 hp D. -228.6 hp

B. -179.5 hp

435. A liquid with a specific gravity of 1.26 is being pumped in a pipeline from A to B. At A, the pipe diameter is 60 cm and the pressure is 300 kN/m2. At B, the pipe diameter is 30 cm and the pressure is 330 kN/m2. Point B is 1.0 m lower than A. Find the flow rate if the pump puts 16 kW into the flow. Neglect head loss. A. 4.2 m3/s B. 0.42 m3/s C. 2.4 m3/s D. 0.24 m3/s

B. 0.42 m3/s

430. A two-stage, double acting compressor is to deliver 90 lb/min of air from 14.3 psia to 90°F to a final pressure of 185 psia. The normal barometer is 29.8 in-Hg and the temperature is 80°F. The pressure drop in the intercooler is 3 psi and the speed is 210 rpm and pV1.34 = C during compression and expansion. The clearance is 5% for both cylinders. Find the volume of free air if the temperature of the cooling water increased by 18°F. A. 1282 CFM B. 1230 CFM C. 1320 CFM D. 1822 CFM

B. 1230 CFM

486. A Carnot cycle has a sink temperature of 100°F and a cycle efficiency of 70%. Find the temperature of the heat souce. A. 1306.70°F B. 1406.70°F C. 1506.70°F D. 1606.70°F

B. 1406.70°F

469. A diesel cycle has an initial temperature of 27°C. If the cut-off ratio is 2.50 and compression ratio is 12, find the maximum cycle temperature. A. 1634.4°C B. 1753.44°C C. 2010.3°C D. 1983.4°C

B. 1753.44°C

441. A centrifugal pump with a 3 ft impeller diameter operates at 800 rpm. If the speed is to be increased to 1200 rpm, determine the impeller diameter that should be used so that the same shaft input power would be required. A. 5.32 ft B. 2.35 ft C. 5.23 ft D. 2.93 ft

B. 2.35 ft

490. Determine the quality of steam in a vessel containing 2 kg of saturated vapor and 8 kg of saturated liquid. A. 100% B. 20% C. 80% D. 60%

B. 20%

416. Calculate the air power of a fan that delivers 1200 m3/min of air through a 1 m x 1.5 m outlet. Static pressure is 120 mm WG and density of air is 1.18. A. 20.45 kW B. 25.64 kW C. 30.45 kW D. 35.64 kW

B. 25.64 kW

423. A pump in a municipality's water-supply system receives water from the filtration beds and pumps it up to the top of a water tower. The tower's height is 35 m, and the inlet piping to the pump is 2 m below the pump's intake. The water temperature is 20 C, measured at both the inlet and the discharge from the pump. The mass flow rate through the pump is 100 kg/s, the diameter of the inlet piping is 25 cm, and the diameter of the discharge piping is 15 cm. Determine the power required by the pump. A. 77.3 kW B. 33.77 kW C. 34.42 kW D. 42.34 kW

B. 33.77 kW

480. Water flows in a pipe at the rate of 10 kg/s. If the velocity of flow is 10 m/s, find the pipe diameter. A. 30.23 mm B. 35.68 mm C. 38.39 mm D. 42.39 mm

B. 35.68 mm

472. An Otto cycle has a clearance of 8% and heat added of 1000 kJ. Find the heat rejected. A. 564 kJ B. 353 kJ C. 709 kJ D. 867 kJ

B. 353 kJ

454. Steam enters a turbine stage with an enthalpy of 3700 kJ/kg and a velocity of 80 m/s and leaves with an enthalpy of 2864 kJ/kg with a velocity of 12.8 m/s. If the rate of a steam flow through the turbine is 0.44 kg/s, what is the work done in kW? A. 365 kW B. 365.64 kW C. 366.0 kW D. 366.50 kW

B. 365.64 kW

478. An automobile tire is inflated to 35 psig at 54°F. After being driven, the temperature rises to 80°F. Determine the final gage pressure assuming that the tire is inflexible. A. 36.51 psig B. 37.51 psig C. 38.51 psig D. 39.51 psig

B. 37.51 psig

483. Calculate the approximate enthalpy of water at 90°C. A. 366.83 kJ/kg B. 376.83 kJ/kg C. 386.83 kJ/kg D. 396.83 kJ/kg

B. 376.83 kJ/kg

467. Flow of water in a pipe has a velocity at 10 meters per second. Determine the velocity head of the water. A. 50.1 meters B. 5.10 meters C. 8.20 meters D. 100 meters

B. 5.10 meters

488. Fifty kilograms of cooling water per second enter the condenser at 25°C and leaves at 50°C. Find the heat carried away by water. A. 1234.45 kW B. 5233.75 kW C. 2340.53 kW D. 3140.25 kW

B. 5233.75 kW

465. An air compressor takes in 9 kg/min of air at 98 kPa; υ1 = 0.125 m3/kg and discharges it at 680 kPa; υ2 = 0.03 m3/kg. The increase of internal energy is 93 kJ/kg and the work done on air is 163 kJ/kg; the change in potential and kinetic energy are neglected. How much heat is transferred per kg of air? A. 264.15 kJ/kg B. 61.85 kJ/kg C. 288.65 kJ/kg D. 78.15 kJ/kg

B. 61.85 kJ/kg

424. An adiabatic tank containing air is used to power an air turbine during times of peak power demand. The tank has a volume of 500 m3 and contains air at 1000 kPa and 500 K. Determine the mass remaining when the pressure reaches 100 kPa. A. 273.37 kg B. 672.73 kg C. 772.73 k D. 227.73 kg

B. 672.73 kg

482. Determine the degrees of superheat of steam at 101.325 kPa and 170°C. A. 50°C B. 70°C C. 60°C D. 80°C

B. 70°C

429. A nozzle receives 0.5 kg/s of air at a pressure of 2700 kPa and a velocity of 30 m/s and with an enthalpy of 923 kJ/kg, and the air leaves at a pressure of 700 kPa and with an enthalpy of 660 kJ/kg. Determine the exit velocity from the nozzle. A. 923 m/s B. 726 m/s C. 700 m/s D. 660 m/s

B. 726 m/s

421. A mixture of 0.4 lbm of helium and 0.2 lbm of oxygen is compressed polytropically from 14.7 psia and 60°F to 60 psia according to n = 1.4. Determine the final temperature, T2. A. 727.7°R B. 777.2°R C. 722.7°R D. 277.7°R

B. 777.2°R

428. A single acting air compressor with a clearance of 6% takes in air at atmospheric pressure and temperature of 85°F and discharges it at a pressure of 85 psia. The air handled is 0.25 ft3/cycle measured at discharge pressure. If the compression is isentropic, find the air hp of the compressor if rpm is 750. A. 16 hp B. 96 hp C. 69 hp D. 61 hp

B. 96 hp

407. A power plant is said to have/had a use factor of 48.5% and a capacity factor of 42.4%. How many hrs. did it operate during the year? A. 6,600.32 hrs B.7,658.23 hrs C. 8,600.32 hrs D. 5,658.23 hrs

B.7,658.23 hrs

431. Consider 4800 lb of steam per hour flowing through a pipe at 100 psia pressure. Assume a velocity of 5280 ft/min. What size of pipe is required? Specific volume of steam at 100 psia υ = 4.432 ft3/lb. A. 3 in B. 5 in C. 4 in D. 6 in

C. 4 in

450. What is the mass of acetylene gas, V = 0.94 cu. ft., R = 59.35 ft-lb/lb-°R, T = 90°F, P = 200 psia? A. 0.816 lb B. 0.841 lb C. 0.829 lb D. 0.852 lb

C. 0.829 lb

493. 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. 212 kJ/kg B. 100 kJ/kg C. 0 kJ/kg D. 331.25 kJ/kg

C. 0 kJ/kg

408. A 50,000 kW steam plant delivers an annual output of 238,000,000 kW-hr with a peak load of 42,860 kW. What is the annual load factor and capacity factor? A. 0.634, 0.534 B. 0.643, 0.534 C. 0.634, 0.543 D. 0.643, 0.534

C. 0.634, 0.543

427. A single acting air compressor with a clearance of 6% takes in air at atmospheric pressure and temperature of 85°F and discharges it at a pressure of 85 psia. The air handled is 0.25 ft3/cycle measured at discharge pressure. If the compression is isentropic, find the piston displacement per cycle, if the compressor is running at 750 rpm. A. 0.0750 ft3/cycle B. 0.025 ft3/cycle C. 1.030 ft3/cycle D. 1.090 ft3/cycle

C. 1.030 ft3/cycle

495. Determine the density of air at 760 mmHg absolute and 22°C? A. 1.014 kg/m3 B. 1.316 kg/m3 C. 1.197 kg/m3 D. 1.266 kg/m3

C. 1.197 kg/m3

442. Determine the mass of water vapor contained in a 150 m3 room at 100 kPa, 23°C and 40% relative humidity. From Steam Tables: Psat @ 23°C = 2.810 kPa. A. 1.6342 kg B. 1.9342 kg C. 1.2342 kg D. 2.2342 kg

C. 1.2342 kg

492. A heat engine has a thermal efficiency of 50%. How much power does the engine produce when heat is transferred at a rate of 109 kJ/hr? A. 50 MW B. 75 MW C. 139 MW D. 147 MW

C. 139 MW

437. The fuel oil has the ff. analysis: C = 89% N2 = 2% H2 = 8% S = 1% With 3% excess air, what is the actual amount of air needed to burn the fuel oil? A. 13.17 kgair/kgfuel C. 14.47 kgair/kgfuel B. 13.47 kgair/kgfuel D. 14.17 kgair/kgfuel

C. 14.47 kgair/kgfuel

477. An air compressor has an inlet enthalpy of 35 Btu/lb and an exit enthalpy of 70 Btu/lb. The mass flow rate of air is 3 lb/s. If the heat loss is 466.62 Btu/min, find the work input to the compressor. A. 139.59 hp B. 149.59 hp C. 159.59 hp D. 169.59 hp

C. 159.59 hp

417. Determine the temperature for which a thermometer with degrees Fahrenheit is numerically twice the reading of the temperature in degrees Celsius. A. -24.6 B. 320 C. 160 D. -12.3

C. 160

462. 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. 17.02 kJ heat rejected C. 17.02 kJ heat added B. 7.05 kJ heat rejected D. 7.05 kJ heat added

C. 17.02 kJ heat added

449. The tank of an air compressor has a volume of 3 ft3 and is filled with air at a temperature of 40°F. If a gage on the tank reads 150 psig, what is the mass of the air in the tank? A. 1.78 lbs B. 2.00 lbs C. 2.67 lbs D. 1.98 lbs

C. 2.67 lbs

463. A Carnot cycle uses nitrogen (k = 1.399) as the working substance. The heat supplied is 54 kJ and the adiabatic expansion ratio is 10. Determine the heat rejected. A. 10 kJ B. 32.4 kJ C. 21.6 kJ D. 54 kJ

C. 21.6 kJ

440. A piston moves inside a cylinder at a velocity of 6.0 m/s. The 160 mm diameter piston is centrally located within the 160.2 mm inside diameter cylinder. The film of oil is separating the piston from the cylinder has an absolute viscosity of 0.4 N-s/m2. Assuming a linear velocity profile, find the shear stress in the oil. (T = μ (v/H)) Given: μ = 0.40 N-s/m2 v = 5 m/s H = thickness of oil film = 160.2 - 160/2 = 0.1 mm A. 50,000 N/m2 B. 40,000 N/m2 C. 24,000 N/m2 D. 34,000 N/m2

C. 24,000 N/m2

401. The water velocity of a 5 m x 1 m channel is 6 m/s. What is the annual energy produced if the net head is 120 m and the over-all efficiency is 80%? A. 494,247,258 kW-hrs C. 247,494,528 kW-hrs B. 247,497,582 kW-hrs D. 472,497,582 kW-hrs

C. 247,494,528 kW-hrs

457. A 35.0 mL sample of gas is enclosed in a flask at 22 degrees Celsius. If the flask was placed in an ice bath at 0 degrees Celsius, what would the new gas volume be if the pressure is held constant? A. 34.1 mL B. 32.1 mL C. 32.39 mL D. 33.1 mL

C. 32.39 mL

415. A pump delivers 20 cfm of water having a density of 62 lb/ft3. The suction and discharge gage reads 5 in. Hg vacuum and 30 psi respectively. The discharge gage is 5 ft above the suction gage. If pump efficiency is 70%, what is the motor power? A. 5.31 HP B. 3.31 HP C. 4.31 HP D. 6.31 HP

C. 4.31 HP

414. A centrifugal pump discharged 20 L/s against a head of 17 m when the speed is 1500 rpm. The diameter of the impeller was 30 cm and the brake horsepower was 6.0. A geometrically similar pump 40 cm in diameter is to run at 1750 rpm. Assuming equal efficiencies, what brake horsepower is required? A. 51.55 HP B. 50.15 HP C. 40.14 HP D. 45.15 HP

C. 40.14 HP

485. A Carnot cycle has a maximum temperature of 550°F and minimum temperature of 100°F. If the heat added is 4200 Btu/min, find the horsepower output of the engine. A. 34.53 B. 40.56 C. 44.13 D. 65.40

C. 44.13

461. A pressure gauge registers 50 psig in a region where the barometer reads 14.8 psia. Find the absolute pressure in kPa. A. 666.66 kPa B. 556.66 kPa C. 446.66 kPa D. 336.66 kPa

C. 446.66 kPa

439. A room contains air at 20°C and 96 kPa at a relative humidity of 75%. Determine the enthalpy of moist air. where: (Psat @ 20°C = 2.339 kPa) (hg @ 20°C = 2538.1 kJ/kgda) Given: Unsaturated air (0% < Ø <100%) td = 20°C Pt = 96 kPa Ø = 75% A. 45.919 kJ/kgda B. 45.515 kJ/kgda C. 49.515 kJ/kgda D. 41.815 kJ/kgda

C. 49.515 kJ/kgda

468. A Diesel cycle has a cut-off ratio of 2.20 and a compression ratio of 10. Find the cycle efficiency. A. 55.10% B. 59.735% C. 52.23% D. 62.37%

C. 52.23%

403. In a hydroelectric power plant the tailwater elevation is at 500 m. What is the head water elevation if the net head is 30 m and the head loss is 5% of the gross head? A. 785.25 m B. 582.57 m C. 528.57 m D. 758.25 m

C. 528.57 m

410. If the air required for combustion is 20 kg per kg of coal and the boiler uses 3000 kg of coal per hr, determine the mass of gas entering the chimney. Assume an ash loss of 15%. A. 40,664 kg/hr B. 70,200 kg/hr C. 62,550 kg/hr D. 50,500 kg/hr

C. 62,550 kg/hr

491. 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/s and the inlet cooling water temperature is 35°C. Calculate the condenser cooling water exit temperature. A. 43.45°C B. 53.45°C C. 63.66°C D. 74.34°C

C. 63.66°C

473. An Otto cycle has a heat rejected of 300 kJ and work of 700 kJ. Find the cycle efficiency. A. 56% B. 60% C. 70% D. 50%

C. 70%

444. Kerosene is pumped into an aircraft fuel tank through a hose that has an inside diameter of 4 cm. If the velocity of the kerosene is 8 m/s through the hose, determine the mass flow rate. Assume that the kerosene has a density of 800 kg/m³. A. 7.06 kg/s B. 7.56 kg/s C. 8.06 kg/s D. 8.56 kg/s

C. 8.06 kg/s

464. A tank contains 20 kg of air at 200 kPa (gage) and 23°C. During the heating process the temperature of air rises. For safety purposes a technician installed a relief-type valve so that pressure of air inside the tank never exceeds 260 kPa (gage). At what air temperature the relief valve will start releasing air? A. 112°C B. 92°C C. 82°C D. 102°C

C. 82°C

448. What is the absolute pressure if the gauge pressure reading is 9 bar and the atmospheric pressure is 0.9 bar? A. 6.3 bar B. 7.8 bar C. 9.9 bar D. 8.1 bar

C. 9.9 bar

487. The quality of steam is 20%. This means that: A. mass of liquid is 20%, mass of vapor is 80% B. mass of liquid is 20%, mass of vapor is 0% C. mass of liquid is 80%, mass of vapor is 20% D. none of the above

C. mass of liquid is 80%, mass of vapor is 20%

425. Determine the air-fuel ratio on a molar basis for the complete combustion of octane, with theoretical amount of air. A. 95.5 kgair/kgfuel B. 59.9 kgair/kgfuel C.59.5 kgair/kgfuel D. 55.9 kgair/kgfuel

C.59.5 kgair/kgfuel

466. During a reversible process, there are abstracted 317 kJ/s from 1.134 kg/s of a certain gas while the temperature remains constant at 26.7°C. For this gas cp = 2.232 and cv = 1.713 kJ/kg-K. The initial pressure is 586 kPa. Determine the final volume flow rate. A. 0.301 m3/s B. 0.03 m3/s C. 0.5 m3/s D. 0.05 m3/s

D. 0.05 m3/s

411. A 15 kg gas enters a chimney at 10 m/s. If the temperature and pressure of a gas are 26°C and 100 kPa respectively, what is the diameter of the chimney? Use R = 0.287 kJ/kg-K. A. 1.57 m B. 2.65 m C. 2.22 m D. 1.28 m

D. 1.28 m

447. Find the density of oil with a specific gravity of 1.6 in-g/cm3. A. 15.68 g/cm3 B. 99.84 g/cm3 C. 0.8 g/cm3 D. 1.6 g/cm3

D. 1.6 g/cm3

443. What is the power of the pump, HP, if it delivers 925 gal/min of water against a head of 15 m? A. 15.38 HP B. 16.38 HP C. 10.5 HP D. 11.5 HP

D. 11.5 HP

475. Find the power of a rotating shaft which develops a torque of 188 N-m at 1350 rpm. A. 101.54 hp B. 53.63 hp C. 63.35 hp D. 35.63 hp

D. 35.63 hp

474. An Otto cycle has a pressure ratio of 7. What is the cycle compression ratio? A. 5.18 B. 6.34 C. 7.34 D. 4.01

D. 4.01

452. A refrigerating system operates on the reversed Carnot Cycle. The higher temperature of the refrigerant in the system is 120°F and the lower is 10°F. The capacity is 20 tons. Neglect losses. Determine the coefficient of performance. A. 2.732 B. 5.373 C. 7.372 D. 4.273

D. 4.273

470. A diesel cycle, which takes in air at 1 bar and 26°C, has a compression ratio of 19. Calculate the operating clearance in percent. A. 8.08 B. 8.56 C. 7.52 D. 5.55

D. 5.55

489. Ten kilograms per second 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 80% and the generator efficiency is 90%, determine the power plant output. A. 4320 kW B. 3213 kW C. 4056 kW D. 5040 kW

D. 5040 kW

426. During a steady state operation, a gearbox receives 60 kW throughout the input shaft and delivers power through the output shaft. For the gearbox as the system, the rate of energy transfer is by convection, h = 0.171 kW/m2-K is the heat transfer coefficient, A = 1.0 m2 is the outer surface area of the gearbox, Tb = 300 K (27°C) is the temperature at the outer surface, Tf = 293 K (20°C) is the temperature of the surroundings away from the immediate vicinity of the gearbox. Determine the power delivered to the output shaft in kW if the heat transfer rate is - 1.2 kW. A. 98.8 kW B. 78.8 kW C. 68.8 kW D. 58.8 kW

D. 58.8 kW

420. A barometer can be used to measure an airplane's altitude by comparing the barometric pressure at a given flying altitude to that on the ground. Determine an airplane's altitude if the pilot measures the barometric pressure at 700 mm-Hg, the ground reports it at 758 mm-Hg, and the average air density is 1.19 kg/m3, g = 9.81 m/s2. A. 636 m B. 633 m C. 366 m D. 663 m

D. 663 m

496. A refrigerating machine that is classified as a one-ton machine has the capacity to produce a cooling effect of? A. 3.516 kW B. 12,000 Btu/hr C. 211 kJ/min D. All of the above

D. All of the above