Thermo Exit Problems Main PDF
Thermo Exit Problems Main PDF
Thermo Exit Problems Main PDF
1 out of 1 points
A 7 ft length of 2 inches diameter pipe is capped and filled with water under 12.5 psi pressure. Placed in a horizontal
position, it is rotated about a vertical axis through one end at the rate of 3 rad/sec. What will be the pressure at the
outer end?
Selected Answer: b.
15.5 psi
Answers: a.
14.6 psi
b.
15.5 psi
c.
15.2 psi
d.
13.1 psi
• Question 2
1 out of 1 points
What force is necessary to lift a thin wire ring 45mm in diameter from a water surface at 20°C (surface tension of
water at 20° C is 0.0728 N/m)? Neglect the weight of the wire.
Selected Answer: b.
0.0206 N
Answers: a.
0.0103 N
b.
0.0206 N
c.
0.0172 N
d.
0.0135 N
• Question 3
1 out of 1 points
A spark-ignition engine produces brake power of 224 KW while using 0.0169 kg/s of fuel. The fuel has a higher
heating value of 44,186 KJ/kg, and the engine has a compression ratio of 8. The frictional power lost is found to be
22.4 KW. Determine the indicated thermal efficiency.
Selected Answer: d.
33
Answers: a.
22
b.
11
c.
44
d.
33
Response Feedback: ei = WKi / QA = WKi / mf x HV = (224 + 22.4) / (0.0169 x 44,186) = 33%
• Question 4
1 out of 1 points
A bracelet which appears to be gold weighs 50 grams in air and 40 grams when submerged in water. Is the bracelet
pure gold? Specific gravity of pure gold is 19.
Selected Answer: c.
Not pure
Answers: a.
None of the other choices
b.
Pure
c.
Not pure
d.
Silver
• Question 5
1 out of 1 points
What is the heat transfer in the glass surface area of 0.7m having an inside temperature of 25C and 13C otuside
temperature. The thickness of glass surface 0.007m. The glass thermal conductivity 1.8W per m per deg K.
Selected Answer: a.
2.2kW
Answers: a.
2.2kW
b.
5.8kW
c.
6.2kW
d.
3.6kW
• Question 6
1 out of 1 points
Assuming isothermal condition, how deep is the pool at a point where an air bubble, upon reaching the surface, has
8 times the volume than it had at the bottom?
Selected Answer: c.
72.3m
Answers: a.
73.3m
b.
71.3m
c.
72.3m
d.
75.5m
Response Feedback: P1V1=P2V2
P2+( h)V1=P2(8V1)
h = 72.3m
• Question 7
1 out of 1 points
Steam at 1000 lbf/ft2
pressure and 3000R
has a specific volume of 6.5 cu. ft/lbm and a specific enthalpy of 9800 lbf-
ft/lbm. Find the internal energy per pound mass of steam.
Selected Answer: a.
3300
Answers: a.
3300
b.
5400
c.
2500
d.
6400
Response Feedback:
lbf-ft/lbm
• Question 8
0 out of 1 points
A thermodynamic cycle looks like an ellipse in the TS diagram. The maximum and minimum temperatures are 533°C
and 124°C, respectively. Calculate the thermal efficiency of the engine.
Selected Answer: c.
50.74%
Answers: a.
49.26%
b.
42.15%
c.
50.74%
d.
57.85%
• Question 9
1 out of 1 points
An engine has an efficiency of 26%. It uses 2 gallons of gasoline per hour. Gasoline has a heating value of 20500
BTU/lbm and a specific gravity of 0.80. What is the power output of the engine?
Selected Answer: b.
20.8kW
Answers: a.
20kW
b.
20.8kW
c.
41.7kW
d.
0.33kW
Response Feedback: mf = fuel consumption
Qs = heat generated
• Question 10
1 out of 1 points
Calculate the logarithmic mean temperature difference for a condenser if the temperature difference between
condensing steam and water inlet is 790C and that steam inlet and water is 100C.
Selected Answer: a.
334C
Answers: a.
334C
b.
425C
c.
555C
d.
225C
• Question 11
1 out of 1 points
A 542 kg hammer of a pile driver is lifted 3.1 meters above a piling head. If the hammer is released, what will be its
velocity (in m/s) at the instant it strikes the piling?
Selected Answer: 95
Correct Answer: 95.00 ± 1
• Question 26
1 out of 1 points
A ball dropped from the roof of a building 74 m high will hit the ground with a velocity of _____ m/s.
Time: 6:00 AM
Oil level in the tank: 7.6 m
Flowmeter reading at inlet: 7,211 liter/minute
Flowmeter reading at outlet: 296 m³/hour
Assuming flow rates remain steady, estimate the level in the tank at 9:00 AM.
• Question 1
0 out of 1 points
The pressure drop across a turbine is 25 psi. The flow rate is 55 gallons per minute. Calculate the power output of
the turbine.
Selected Answer: c.
0.41hp
Answers: a.
1.05hp
b.
2.54hp
c.
0.41hp
d.
0.802hp
Response Feedback:
• Question 2
1 out of 1 points
A coil spring hanging from a hook stretches 3cm when a 2N weight is attached. What weight would be required to
lengthen the spring to a length of 7.5 cm?
Selected Answer: d.
5N
Answers: a.
7.5N
b.
2.5N
c.
10N
d.
5N
Response Feedback:
F2=5N
• Question 3
1 out of 1 points
The compression ratio of an ideal Otto cycle is 6:1. Initial conditions are 101.325 KPa and 20°C. Find the
temperature at the end of the adiabatic compression.
Selected Answer: c.
600K
Answers: a.
60K
b.
600C
c.
600K
d.
60C
Response Feedback:
T2 = 599.96°K
• Question 4
1 out of 1 points
An ideal gas at 0.60 atmosphere and 87°C occupies 0.450 liter. How many moles are in the sample? L-
atm/mole-K
Selected Answer: c.
0.0091mole
Answers: a.
0.0002mole
b.
0.098mole
c.
0.0091mole
d.
0.0378mole
Response Feedback:
mole
• Question 5
0 out of 1 points
Assuming a shaft output of 3000 kw and a fuel rate of 34.2 lbs/min. What is the overall thermal efficiency of the
machine? (HHV of fuel is 18000 BTU/lb)
Selected Answer: c.
24.2%
Answers: a.
29.1%
b.
27.1%
c.
24.2%
d.
28.3%
Response Feedback:
Thermal Efficiency
• Question 6
1 out of 1 points
If air is at pressure, p of 3200 lbf/ft2, and at a temperature, T of 800°R, what is the specific volume, v? (R = 53.3 ft-
lbf/lbm-°R and air can be modeled as an ideal gas)
Selected Answer: a.
13.3cu.ft/lbm
Answers: a.
13.3cu.ft/lbm
b.
14.2cu.ft/lbm
c.
11.2cu.ft/lbm
d.
9.8cu.ft/lbm
Response Feedback:
• Question 7
0 out of 1 points
A water tank is 18ft wide, 14ft long and 4 ft high. Calculate the pressure at the bottom of the tank.
Selected Answer: c.
2.337psi
Answers: a.
1.999psi
b.
1.733psi
c.
2.337psi
d.
3.773psi
Response Feedback:
P=62.4x4/144=1.733lb/in
• Question 8
0 out of 1 points
Two tubes are mounted to the roof of a car. One tube points to the front of the car while the other points to the rear.
The tubes are connected to a manometer fitted with a fluid of specific gravity 0.60. When the height difference is 2
inches, what is the car’s speed?
Selected Answer: c.
62mph
Answers: a.
50mph
b.
43.8mph
c.
62mph
d.
46mph
108HP
Answers: a.
108HP
b.
28HP
c.
256HP
d.
1390HP
Response Feedback:
• Question 10
1 out of 1 points
A plaster wall which is 20 cm thick with a thermal conductivity of 0.3W/m C is used in a certain house. The inner
wall temperature is at 40C, and the outer wall is exposed to ambient wind and the surroundings at 12C. The film
coefficient, h, for convective heat transfer in a 10m/s wind is about 21W/m C. Ignoring any radiation losses, find
the overall coefficient for the conduction and convection losses in W/m C
Selected Answer: c.
1.4
Answers: a.
8.1
b.
10.1
c.
1.4
d.
• Question 11
1 out of 1 points
A 549 kg hammer of a pile driver is lifted 3 meters above a piling head. If the hammer is released, what will be its
velocity (in m/s) at the instant it strikes the piling?
• Question 12
0 out of 1 points
A power station uses oil-fired boilers which are supplied with fuel from 5 cylindrical tanks, each with 14 m diameter
and 10 m high. The calorific value of the oil is 38,185 kJ/kg and its relative density is 0.81. The output from the
power station is 69 MW. Assuming the only 15% of the heat input is converted to into electrical energy output, how
long will the boilers run (in days) on the oil in the tanks.
Selected Answer: 4
• Question 13
0 out of 1 points
A tank contains 24 liters of lubricating oil having a relative density of 0.89 and a temperature of 12 ºC. The oil is
heated for 14 minutes by a 2.01 kW electric heater. Determine the final temperature (in ºC) of the oil assuming a
heat loss of 176 W on the tank. (cp oil is 1.9 kJ/kg-K)
Selected Answer: 86
Correct Answer: 49.96 ± 1%
• Question 14
1 out of 1 points
A liquid to liquid counterflow heat exchanger is used to heat a cold fluid from 85 ºF to 288 ºF. Assuming that the hot
fluid enters at 533 ºF and leaves at 404 ºF, calculate the log mean temperature in ºF for the heat exchanger.
• Question 15
0 out of 1 points
One kg of water initially at 21 ºC is to be freeze at –5ºC. Calculate the total amount of heat (in kJ) to be removed
during the cooling process? Cp(ice) = 0.5(Cpw)
Selected Answer: 172
• Question 16
1 out of 1 points
An ideal gas at 40 psig and 70 °F is heated in a closed container to 129°F. What is the final pressure in psia?
• Question 17
0 out of 1 points
How far below the water surface (in m) should the center of a vertical square 1.5 m on a side with two sides
horizontal to be immersed so that the center of pressure will be 53 mm below the center of gravity?
• Question 18
1 out of 1 points
What is the ºAPI if the specific gravity at 15.6 ºC is 0.893?
• Question 19
1 out of 1 points
What is the absolute pressure (kPa) if the vacuum pressure is 24 kPa?
• Question 20
0 out of 1 points
In an oil refinery, cylindrical tank of 18 m in diameter and 18 m height is used to store crude oil. A process
technician notes down the following data.
Time: 7:00 AM
Oil level in the tank: 7.4 m
Flowmeter reading at inlet: 7,542 liter/minute
Flowmeter reading at outlet: 300 m³/hour
Assuming flow rates remain steady, estimate the level in the tank at 9:00 AM.
Selected Answer: 12
• Question 21
1 out of 1 points
A ball dropped from the roof of a building 93 m high will hit the ground with a velocity of _____ m/s.
• Question 22
0 out of 1 points
Steam enters a nozzle steadily with a velocity of 149 m/s and enthalpy of 1,490 KJ/kg and leaves with an enthalpy
of 1,001 KJ/kg. Neglecting heat transfer, what is the velocity of steam at the nozzle outlet in m/s?
• Question 23
0 out of 1 points
An open tank 1.16 meter in diameter and 1.5 m height is filled with diesel oil (S.G. = 0.84). Assuming 74% of its
capacity is occupied by the diesel; calculate the absolute pressure (in kPa) of the fluid at the bottom of the tank.
• Question 24
0 out of 1 points
A Carnot engine requires 37 kW from the hot source. The engine produces 17 kW of power and the temperature of
the sink is 27 °C. What is the temperature of the hot source in ºC?
Selected Answer: 20
Correct Answer: 282.13 ± 0.1
• Question 25
0 out of 1 points
A rocket of mass 1.7x104 kg accelerates at 229 m/s2 for 30 s from an initial speed of 5,121 m/s. How much kinetic
energy (in J) has the rocket gained?
Selected Answer: 1.4866500E7
• Question 26
0 out of 1 points
Steam flows into a turbine at the rate of 9 kg/s and 30 KW of heat are lost from the turbine. Ignoring elevation and
kinetic energy effects, calculate the power output from the turbine in kW.
• Question 27
0 out of 1 points
A Carnot engine receives 142 BTU of heat form a hot reservoir at 831 °F and rejects 50 BTU of heat. Calculate the
temperature of the cold reservoir.
• Question 28
0 out of 1 points
If 3 kg metal with 94 ºC temperatures is immersed into 7 kg of water at 9 ºC, what will be the final temperature of
the water after immersion? Cp metal = 0.91 KJ/kg-K
• Question 29
0 out of 1 points
Determine the change in entropy (BTU/R) in an isothermal process having an initial volume of 19 cu ft and a final
volume of 23 cu ft. The mass is 13 lb and the specific heat is 0.24 BTU/lb-R.
• Question 30
0 out of 1 points
What is the Reynolds number of a fluid flowing in a tube with an inside diameter of 3 inches? The viscocity is 1.379
x 10^ -5 lb/ft-s and the mass flow rate is 78 lb/h.
Selected Answer: [None Given]
• Question 31
0 out of 1 points
A centrifugal pump uses a 121,226 rpm motor to pump 101,960 kg/min of standard temperature water and has a
pressure rise from 4 bar to 38 bar using a 0.1 cm diameter impeller. The inlet diameter is 0.32 cm and the outlet
diameter is 0.16 cm. The inlet and outlet are at the same level with each other.
• Question 32
0 out of 1 points
A 53 kW electric furnace measures 1.1m x 1.5m x 0.8m. When the temperature inside the furnace is 1,680 ºC, a
block of aluminum with a mass of 398 kg and a temperature of 17 ºC is placed inside. Assuming the heat loss from
the furnace walls is 474 W/m, how long (in min) will it take to heat the block to the furnace temperature? (Specific
heat of aluminum is 0.9 kJ/kg. K)
• Question 33
0 out of 1 points
Determine the resistance (in F-h/BTU) of a hollow cylinder with an inside and outside radius of 2 in and 2.1 in,
respectively. The length of the cylinder is 7 ft while the thermal conductivity is 23 BTU/hr-ft-F
• Question 34
0 out of 1 points
Calculate the amount of energy (in BTU) required to heat the air in a house 21 ft by 23 ft by 46 ft from 19 to 98 ºF.
The density of air is 0.08 lb/ft3.
Selected Answer: [None Given]
Correct Answer: 33,700.26 ± 1%
• Question 35
0 out of 1 points
In an exothermic process, the volume of a system expanded from 152 mL to 1,896 mL against a constant pressure of
751 torr. During the process, 23.5 calories of heat energy were given off. What was the internal energy change for
the system in joules?
• Question 36
1 out of 1 points
What retarding force (in N) is required to stop a 0.45 caliber bullet of mass 18 grams and speed of 412 m/sec as it
penetrates a wooden block to a depth of 4 inches?
• Question 37
0 out of 1 points
A centrifugal pump uses a 138,580 rpm motor to pump 101,660 kg/min of standard temperature water and has a
pressure rise from 2 bar to 31 bar using a 0.11 cm diameter impeller. The inlet diameter is 0.39 cm and the outlet
diameter is 0.19 cm. The inlet and outlet are at the same level with each other.
• Question 38
0 out of 1 points
An airplane has a mass of 202,089 kg and carries 354 passengers having an average mass of 61 kg each. What is the
total energy of the loaded airplane (in MJ) when traveling at 813 km/hr at a height of 9,612 m above the sea level?
• Question 39
0 out of 1 points
The surface tension of water is 0.072 N/m. Find the weight of water in μN supported by surface tension in a
capillary tube with radius of 0.22 mm.
• Question 40
1 out of 1 points
The maximum thermal efficiency (in %) possible for a power cycle operating between 1,357 °F and 206°F is:
• Question 1
1 out of 1 points
The theoretical velocity, in fps, generated by a 10 foot hydraulic head is:
Selected Answer: b.
25.4
Answers: a.
12.2
b.
25.4
c.
17.9
d.
29.2
• Question 2
0 out of 1 points
A 7 ft length of 2 inches diameter pipe is capped and filled with water under 12.5 psi pressure. Placed in a horizontal
position, it is rotated about a vertical axis through one end at the rate of 3 rad/sec. What will be the pressure at the
outer end?
Selected Answer: b.
15.2 psi
Answers: a.
15.5 psi
b.
15.2 psi
c.
13.1 psi
d.
14.6 psi
• Question 3
1 out of 1 points
The static head corresponding to a flow velocity of 10m/s is
Selected Answer: a.
5.09
Answers: a.
5.09
b.
8.36
c.
1.67
d.
6.1
Response Feedback:
H = 10 /(2*9.81)
• Question 4
0 out of 1 points
Calculate from the following data, the kg of air per kg of fuel used by an automobile engine: air temperature is
21.50ºC, barometer reads 760 mm Hg, air entering 1.75 m3/min., measured gasoline 14.25 liters per hr, specific
gravity of gasoline 0.735.
Selected Answer: c.
15.45
Answers: a.
21.45
b.
14.45
c.
15.45
d.
12.02
Response Feedback: ma =PV/RT = (101.325 x 1.75) / 0.287)(294.5) = 2.098 Kg/min
mf = ñ x v =0.735 (1,000) x (0.01425)/(60) = 0.1746 kg/min
ra/f = 2.098 / 0.1746 = 12.02 kga/kgf
• Question 5
1 out of 1 points
Helium is compressed isothermally from 14.7 psia and 68F. The compression ratio is 4. Calculate the change in
• Question 9
0 out of 1 points
An engine has an efficiency of 26%. It uses 2 gallons of gasoline per hour. Gasoline has a heating value of 20500
BTU/lbm and a specific gravity of 0.80. What is the power output of the engine?
Selected Answer: a.
0.33kW
Answers: a.
0.33kW
b.
41.7kW
c.
20.8kW
d.
20kW
Response Feedback:
• Question 10
1 out of 1 points
Clapeyron-Clausius equation is used to estimate saturation condition of the fluid at small intervals. Approximate
the saturation pressure of water at 120° given that the Clapeyron-Clausius equation
is .
Selected Answer: c.
197.3 kPa
Answers: a.
161.8 kPa
b.
213.2 kPa
c.
197.3 kPa
d.
135.2 kPa
• Question 11
0 out of 1 points
The fluid in a manometer tube is 60 % water and 40 % alcohol (S.G. = 0.83). What is the manometer fluid height
difference (in ft) if a 9.5 psi pressure is applied across the two ends of a manometer?
Time: 6:00 AM
Oil level in the tank: 7.7 m
Flowmeter reading at inlet: 7,928 liter/minute
Flowmeter reading at outlet: 295 m³/hour
Assuming flow rates remain steady, estimate the level in the tank at 10:00 AM.
• Question 1
1 out of 1 points
What is the static head corresponding to a flow velocity of 10 ft/sec?
Selected Answer: c.
1.55ft
Answers: a.
2.25ft
b.
2.05ft
c.
1.55ft
d.
1.75ft
• Question 2
0 out of 1 points
Two different types of heat exchangers are being considered – parallel flow and counter flow. The heating fluid is water at a rate
of 4 kg/min, which enters at and leaves at . The heated fluid is also water at a rate of 8.0 kg/min. It enters
at and leaves at . What would be the relative sizes of the two types of heat exchangers?
Selected d.
Answer: The parallel flow heat exchanger would be 5% smallerThe parallel flow heat exchanger would be 5%
smaller
Answers: a.
The parallel flow heat exchanger would be 6% larger
b.
They would be equal in size
c.
The counter flow heat exchanger would be 10% larger
d.
The parallel flow heat exchanger would be 5% smallerThe parallel flow heat exchanger would be 5%
smaller
• Question 3
1 out of 1 points
A bicycle tire has a volume of 600 cu. cm. It is inflated with carbon dioxide to pressure, of 80 psi at 20°C. How
many grams of carbon dioxide are contained in the tire?
Selected Answer: c.
5.98g
Answers: a.
6.43g
b.
3.83g
c.
5.98g
d.
4.63g
Response Feedback: M = mol. wt. of CO2 = 44
• Question 4
0 out of 1 points
Helium is compressed isothermally from 14.7 psia and 68F. The compression ratio is 4. Calculate the change in
entropy of the gas given that .
Selected Answer: c.
0 BTU/lbm-R
Answers: a.
0.689 BTU/lbm-R
b.
-2.76 BTU/lbm-R
c.
0 BTU/lbm-R
d.
-0.689 BTU/lbm-R
• Question 5
0 out of 1 points
A cold soda initially at 3C gains 30kJ of heat in a room at 22C during a 20-minute period. What is the average rate
of heat transfer during the process?
Selected Answer: d.
12W
Answers: a.
20W
b.
18W
c.
10W
d.
12W
• Question 6
1 out of 1 points
At an average temperature of 100°C, hot air flows through a 2.5 m long tube with an inside diameter of 50
mm. The temperature of the tube is 20°C along its entire length. Convective film coefficient is 20.1 W/m2-
°K. Determine the convective heat transfer form air to the tube.
Selected Answer: d.
632W
Answers: a.
900W
b.
909W
c.
624W
d.
632W
Response Feedback: A = heat transfer area = pi × D × L
= pi × (0.050) × (2.5) = 0.3927 m2
QC = hC × A × (t2 – t1)
QC = 20.1 × (0.3927 × (100 – 20)
QC = 631.5 W
• Question 7
1 out of 1 points
A coil spring hanging from a hook stretches 3cm when a 2N weight is attached. What weight would be required to
lengthen the spring to a length of 7.5 cm?
Selected Answer: d.
5N
Answers: a.
7.5N
b.
2.5N
c.
10N
d.
5N
Response Feedback:
F2=5N
• Question 8
0 out of 1 points
If the atmospheric pressure is 14.6 psia (100.7 kPa) and the local gravity is 28 ft/sec2 (8.5 m/sec2), what would be
the maximum height that a vacuum pump can lift 60°F (15°C) water? Answer in S.I.
Selected Answer: d.
9.5m
Answers: a.
10.5m
b.
11.8m
c.
7.5m
d.
9.5m
Response Feedback:
• Question 9
1 out of 1 points
In a constant temperature, closed system process, 100 BTU of heat is transferred to the working fluid at 100°F.
What is the change in entropy of the working fluid?
Selected Answer: d.
0.34kJ/K
Answers: a.
0.25kJ/K
b.
0.18kJ/K
c.
0.57kJ/K
d.
0.34kJ/K
Response Feedback:
• Question 10
0 out of 1 points
What is the efficiency of an Otto cycle with a compression ratio of 6:1? The gas used is air.
Selected Answer: a.
0.167
Answers: a.
0.167
b.
0.191
c.
0.512
d.
0.488
Response Feedback: For an Otto cycle:
Efficiency
• Question 11
0 out of 1 points
A centrifugal pump uses a 130,300 rpm motor to pump 118,905 kg/min of standard temperature water and has a
pressure rise from 3 bar to 35 bar using a 0.1 cm diameter impeller. The inlet diameter is 0.33 cm and the outlet
diameter is 0.19 cm. The inlet and outlet are at the same level with each other.
Time: 7:00 AM
Oil level in the tank: 7.2 m
Flowmeter reading at inlet: 7,663 liter/minute
Flowmeter reading at outlet: 295 m³/hour
Assuming flow rates remain steady, estimate the level in the tank at 9:00 AM.
KW
• Question 2
1 out of 1 points
The static head corresponding to a flow velocity of 10m/s is
Selected Answer: b.
5.09
Answers: a.
1.67
b.
5.09
c.
8.36
d.
6.1
Response Feedback:
H = 10 /(2*9.81)
• Question 3
1 out of 1 points
A transportation company specializes in the shipment of pressurized gaseous materials. An order is received for
100 litres of a particular gas at STP (32°F and 1 atm). What minimum volume tank is necessary to transport the
gas at 80°F and a maximum pressure of 8 atm?
Selected Answer: d.
14L
Answers: a.
12L
b.
16L
c.
10L
d.
14L
Response Feedback:
• Question 4
1 out of 1 points
What is the static head corresponding to a flow velocity of 10 ft/sec?
Selected Answer: c.
1.55ft
Answers: a.
2.05ft
b.
2.25ft
c.
1.55ft
d.
1.75ft
• Question 5
1 out of 1 points
Steam at 1000 lbf/ft2 pressure and 3000R has a specific volume of 6.5 cu. ft/lbm and a specific enthalpy of 9800 lbf-
ft/lbm. Find the internal energy per pound mass of steam.
Selected Answer: d.
3300
Answers: a.
5400
b.
2500
c.
6400
d.
3300
Response Feedback:
lbf-ft/lbm
• Question 6
1 out of 1 points
If an initial volume of an ideal gas is compressed to one-half its original volume and to twice its original
temperature, the pressure_____________.
Selected Answer: b.
quadruples
Answers: a.
doubles
b.
quadruples
c.
remains constant
d.
halves
Response Feedback:
• Question 7
1 out of 1 points
In an isentropic process, P1 = 200 psi , P2 = 300psi and T1 = 700R . Find T2 , using k=1.4 .
Selected Answer: d.
786R
Answers: a.
680R
b.
567R
c.
590R
d.
786R
• Question 8
1 out of 1 points
What force is necessary to lift a thin wire ring 45mm in diameter from a water surface at 20°C (surface tension of
water at 20° C is 0.0728 N/m)? Neglect the weight of the wire.
Selected Answer: c.
0.0206 N
Answers: a.
0.0135 N
b.
0.0172 N
c.
0.0206 N
d.
0.0103 N
• Question 9
1 out of 1 points
If the absolute pressure at the bottom of the ocean is 120kPa, how deep is the water at this point? S.G. sea water =
1.03
Selected Answer: d.
1.85m
Answers: a.
1.55m
b.
1.68m
c.
1.9m
d.
1.85m
Response Feedback: Pg = 120-101.325 = 18.675kPa
H = 18.675/(1.03*9.81) = 1.85m
• Question 10
0 out of 1 points
Determine the friction head loss for fully developed laminar flow of ethylene glycol at 40C ( =1101 )
through a 5cm diameter, 50m long pipe, if friction factor is 0.242 and a flow rate of 0.1 kg/s
Selected Answer: b.
3.46m
Answers: a.
6.42m
b.
3.46m
c.
5.32m
d.
2.64m
Response Feedback: v = 0.4626m/s
hf = fLv /2gD = 0.242x50x0.4626 /(2*9.81*.05) = 2.64m
• Question 11
0 out of 1 points
A tank contains 19 liters of lubricating oil having a relative density of 0.89 and a temperature of 10 ºC. The oil is
heated for 11 minutes by a 2.03 kW electric heater. Determine the final temperature (in ºC) of the oil assuming a
heat loss of 207 W on the tank. (cp oil is 2 kJ/kg-K)
?
?
• Question 1
1 out of 1 points
The pressure drop across a turbine is 25 psi. The flow rate is 55 gallons per minute. Calculate the power output of
the turbine.
Selected Answer: d.
0.802hp
Answers: a.
1.05hp
b.
2.54hp
c.
0.41hp
d.
0.802hp
Response Feedback:
• Question 2
1 out of 1 points
What pressure is a column of water 100 cm high equivalent to?
Selected Answer: d.
9807 N/m2
Answers: a.
98,100 Pa
b.
9807 D/cm2
c.
0.1 bar
d.
9807 N/m2
Response Feedback:
• Question 6
1 out of 1 points
A 10-kg block is raised vertically 3 meters. What is the change in potential energy. Answer in SI units is closest to:
Selected Answer: d.
294J
Answers: a.
350kg·m2/s2
b.
320J
c.
350N-m
d.
294J
Response Feedback:
• Question 7
0 out of 1 points
An Otto engine has clearance volume of 7%. It produces 300 KW power. What is the amount of heat rejected in
KW?
Selected Answer: c.
160
Answers: a.
95.32
b.
152
c.
160
d.
92.16
Response Feedback:
r = compression ratio = =
e= = = 0.664
QR = 152 kW
• Question 8
1 out of 1 points
Ice in an iceberg has a specific gravity of 0.922. When floating in seawater (specific gravity of 1.03), its exposed volume % is
nearest to:
Selected Answer: b.
10.5
Answers: a.
5.6
b.
10.5
c.
7.4
d.
8.9
• Question 9
1 out of 1 points
A vessel with a volume of 1 cubic meter contains liquid water and water vapor in equilibrium at 600 kPa. The
liquid water has a mass of 1 kg. From steam table; vf = 0.001101m3/kg and vg = 0.3157 m3/kg.
Selected Answer: b.
3.16kg
Answers: a.
0.99kg
b.
3.16kg
c.
1.89kg
d.
1.57kg
Response Feedback:
Volume of liquid
Volume of vapor =
• Question 10
1 out of 1 points
The theoretical velocity, in fps, generated by a 10 foot hydraulic head is:
Selected Answer: b.
25.4
Answers: a.
17.9
b.
25.4
c.
12.2
d.
29.2
• Question 11
1 out of 1 points
The weight of 1 liter of gasoline is 7.09 N. Determine its density in kg/m 3.
Selected Answer: 722.73
Correct Answer: 722.73 ± 0.1
• Question 12
1 out of 1 points
If 3.6 kg metal with 103 ºC temperatures is immersed into 5 kg of water at 9 ºC, what will be the final temperature
of the water after immersion? Cp metal = 0.911 KJ/kg-K
Selected Answer: 47
Correct Answer: 47
• Question 28
1 out of 1 points
A ball dropped from the roof of a building 82 m high will hit the ground with a velocity of _____ m/s.
Time: 7:00 AM
Oil level in the tank: 7 m
Flowmeter reading at inlet: 7,057 liter/minute
Flowmeter reading at outlet: 297 m³/hour
Assuming flow rates remain steady, estimate the level in the tank at 9:00 AM.
Question 1
0 out of 1 points
A plaster wall which is 20 cm thick with a thermal conductivity of 0.3W/m C is used in a certain house. The
inner wall temperature is at 40C, and the outer wall is exposed to ambient wind and the surroundings
at 12C. The film coefficient, h, for convective heat transfer in a 10m/s wind is about 21W/m C. Ignoring
any radiation losses, find the overall coefficient for the conduction and convection losses in W/m C
Selected Answer: a.
Answers: a.
b.
1.4
c.
10.1
d.
8.1
Question 2
1 out of 1 points
Determine the force in Newtons required to produce an acceleration of 0.3 m/s 2 on a 0.05 kg mass.
Selected Answer: c.
0.015N
Answers: a.
0.018N
b.
.020N
c.
0.015N
d.
0.025N
Response Feedback: F = ma = 0.05 × (0.3) = 0.015 N
Question 3
1 out of 1 points
Selected Answer: a.
5.09
Answers: a.
5.09
b.
6.1
c.
8.36
d.
1.67
Question 4
0 out of 1 points
Two different types of heat exchangers are being considered – parallel flow and counter flow. The heating fluid is
water at a rate of 4 kg/min, which enters at and leaves at . The heated fluid is also water at a rate of 8.0 kg/min. It
enters at and leaves at . What would be the relative sizes of the two types of heat exchangers?
Selected c.
Answer:
The parallel flow heat exchanger would be 5% smallerThe parallel flow heat exchanger would
be 5% smaller
Answers: a.
b.
c.
The parallel flow heat exchanger would be 5% smallerThe parallel flow heat exchanger would
be 5% smaller
d.
Question 5
1 out of 1 points
Normal boiling point of liquid oxygen is 90K . What is this temperature in °R?
Selected Answer: d.
162
Answers: a.
-183
b.
-330
c.
168
d.
162
Question 6
1 out of 1 points
What is the temperature in degree C of 2 liters of water at 30 degree C after 500 calories of heat have
been added to?
Selected Answer: a.
30.25C
Answers: a.
30.25C
b.
39.75C
c.
38C
d.
35.7C
Response Feedback: Q = m × cp × (t2 – t1)
t2 = 30.25°C
Question 7
1 out of 1 points
Selected Answer: b.
25.4
Answers: a.
12.2
b.
25.4
c.
17.9
d.
29.2
Question 8
1 out of 1 points
At an average temperature of 100°C, hot air flows through a 2.5 m long tube with an inside diameter of 50
mm. The temperature of the tube is 20°C along its entire length. Convective film coefficient is 20.1 W/m 2-
°K. Determine the convective heat transfer form air to the tube.
Selected Answer: b.
632W
Answers: a.
624W
b.
632W
c.
909W
d.
900W
QC = 631.5 W
Question 9
1 out of 1 points
In a constant temperature, closed system process, 100 BTU of heat is transferred to the working fluid at
100°F. What is the change in entropy of the working fluid?
Selected Answer: b.
0.34kJ/K
Answers: a.
0.25kJ/K
b.
0.34kJ/K
c.
0.18kJ/K
d.
0.57kJ/K
Response Feedback:
Question 10
1 out of 1 points
The sun generates 1 kW/m2 when used as a source for solar collectors. A collector with an area of 1
m2 heats water. The flow rate is 3.0 liters/min. What is the temperature rise in the water? The specific
heat of water is 4,200 J/kg -°C.
Selected Answer: c.
4.8C
Answers: a.
8.4C
b.
.48C
c.
4.8C
d.
.56C
Response Feedback:
Question 11
0 out of 1 points
Determine the resistance (in F-h/BTU) of a hollow cylinder with an inside and outside radius of 2 in and 2.1
in, respectively. The length of the cylinder is 3 ft while the thermal conductivity is 24 BTU/hr-ft-F
Selected Answer: [None Given]
Question 12
0 out of 1 points
A Carnot engine requires 37 kW from the hot source. The engine produces 22 kW of power and the
temperature of the sink is 28 °C. What is the temperature of the hot source in ºC?
Question 13
1 out of 1 points
Question 14
1 out of 1 points
A liquid to liquid counterflow heat exchanger is used to heat a cold fluid from 100 ºF to 264 ºF.
Assuming that the hot fluid enters at 539 ºF and leaves at 379 ºF, calculate the log mean temperature in
ºF for the heat exchanger.
Question 15
0 out of 1 points
In a diesel cycle, what is the expansion ratio if the % clearance is 1/16 while the cut-off ratio is 2.7?
Question 16
0 out of 1 points
A tank contains 24 liters of lubricating oil having a relative density of 0.88 and a temperature of 9 ºC. The
oil is heated for 14 minutes by a 2.03 kW electric heater. Determine the final temperature (in ºC) of the oil
assuming a heat loss of 200 W on the tank. (cp oil is 2 kJ/kg-K)
A Carnot engine receives 120 BTU of heat form a hot reservoir at 740 °F and rejects 58 BTU
of heat. Calculate the temperature of the cold reservoir.
Question 18
1 out of 1 points
A ball dropped from the roof of a building 95 m high will hit the ground with a velocity of _____ m/s.
A rocket of mass 1.8x104 kg accelerates at 208 m/s2 for 20 s from an initial speed of 5,477 m/s. How much
kinetic energy (in J) has the rocket gained?
Question 20
0 out of 1 points
Steam flows into a turbine at the rate of 8 kg/s and 42 KW of heat are lost from the turbine. Ignoring
elevation and kinetic energy effects, calculate the power output from the turbine in kW.
Question 21
0 out of 1 points
A power station uses oil-fired boilers which are supplied with fuel from 4 cylindrical tanks, each with 12
m diameter and 11 m high. The calorific value of the oil is 38,039 kJ/kg and its relative density is 0.78. The
output from the power station is 77 MW. Assuming the only 21% of the heat input is converted to into
electrical energy output, how long will the boilers run (in days) on the oil in the tanks.
Question 22
0 out of 1 points
The % clearance of an Otto cycle is 0.186. If the initial pressure is 33 kPag, determine the final pressure.
Selected Answer: [None Given]
Question 23
0 out of 1 points
Determine the change in entropy (BTU/R) in an isothermal process having an initial volume of 6 cu ft
and a final volume of 43 cu ft. The mass is 51 lb and the specific heat is 0.24 BTU/lb-R.
Question 24
0 out of 1 points
What is the Reynolds number of a fluid flowing in a tube with an inside diameter of 1 inches? The
viscocity is 1.353 x 10^ -5 lb/ft-s and the mass flow rate is 79 lb/h.
Question 25
1 out of 1 points
A box has a mass of 14.4 kg. The box is lifted from the garage floor and placed on a shelf. If the box
gains 208 J of Potential Energy, how high is the shelf in meters?
Question 26
1 out of 1 points
A 663 kg hammer of a pile driver is lifted 3.3 meters above a piling head. If the hammer is released,
what will be its velocity (in m/s) at the instant it strikes the piling?
Question 27
0 out of 1 points
The maximum thermal efficiency (in %) possible for a power cycle operating between 1,064 °F and
230°F is:
Question 28
0 out of 1 points
The thermal conductivity of a fluid is 0.09 BTU/ft-h-F having a kinematic viscosity of 0.0215 ft2/h. If the
density and specific heat at constant pressure are 53 lbm/ft3 and 0.43 BTU/lb-F, respectively, determine
the Prandtl number.
Question 29
1 out of 1 points
Question 30
0 out of 1 points
An airplane has a mass of 208,640 kg and carries 400 passengers having an average mass of 64 kg each.
What is the total energy of the loaded airplane (in MJ) when traveling at 781 km/hr at a height of 9,849 m
above the sea level?
Question 31
0 out of 1 points
A centrifugal pump uses a 120,656 rpm motor to pump 118,698 kg/min of standard temperature water and
has a pressure rise from 3 bar to 38 bar using a 0.11 cm diameter impeller. The inlet diameter is 0.31 cm and
the outlet diameter is 0.15 cm. The inlet and outlet are at the same level with each other.
?
Selected Answer: [None Given]
Question 32
0 out of 1 points
In an oil refinery, cylindrical tank of 21 m in diameter and 16 m height is used to store crude oil. A
process technician notes down the following data.
Time: 6:00 AM
Oil level in the tank: 7.2 m
Flowmeter reading at inlet: 7,821 liter/minute
Question 33
0 out of 1 points
Question 34
0 out of 1 points
Steam enters a nozzle steadily with a velocity of 131 m/s and enthalpy of 1,339 KJ/kg and leaves with an
enthalpy of 1,059 KJ/kg. Neglecting heat transfer, what is the velocity of steam at the nozzle outlet in m/s?
Question 35
0 out of 1 points
An ideal gas at 52 psig and 87 °F is heated in a closed container to 136°F. What is the final pressure in
psia?
Question 36
0 out of 1 points
If the velocity of discharge from a fire hose is 21 m/s and the hose is oriented at 34º from
the horizontal, disregarding air friction, determine the maximum range of discharge (in m).
Question 37
0 out of 1 points
Question 38
0 out of 1 points
Calculate the enthalpy in kJ of 1.7 kg of fluid that occupy a volume of 0.695 m3 if the internal
energy is 550.9 kcal per kg and the pressure is 2.1 atm.
Question 39
0 out of 1 points
What is the kinetic energy if the mass is 63 lb and the 13is 2 ft/s in ft-lbf?
Question 40
0 out of
1
points
Hot gases at 286 ºC flow on one side of a metal plate of 18 mm thickness and air at 46 ºC flows
on the other side. The heat transfer coefficient of the gases is 31.2 W/m 2-K and that of the air
is 31.7 W/m2-K. Calculate the over-all heat transfer coefficient if the value of the thermal
conductivity is 7 W/m-K.