101-200

199. An ideal gas mixture consists of 2 kmol of N2 and 6 kmol of CO2. The apparent gas constant of mixture is? A. 0.208 B. 0.231 C. 0.531 D. 0.825

A. 0.208

112. A single acting compressor has a volumetric efficiency of 89%, operates at 500 rpm. It takes in air at 100 kPa and 30°C and discharges it at 600 kPa. The air handled is 8 m3/min measured at discharged condition. If compression is isentropic, find the effective mean pressure in kPa. A. 233.34 B. 973.17 C. 198.34 D. 204.82

A. 233.34

145. Air enters a diffuser with a velocity of 200 m/s. Determine the velocity of sound if air temperature is 30°C. A. 349 m/s B. 359 m/s C. 369 m/s D. 379 m/s

A. 349 m/s

142. Air flows through a nozzle at a speed of 350 m/s. Find the stagnation temperature if the entrance temperature is 200°C. A. 241.25°C B. 251.25°C C. 261.25°C D. 271.25°C

C. 261.25°C

110. A two stage air intercooler has an intercooler pressure of 4 kg/cm2. What is the discharge pressure if suction pressure is 1 kg/cm2? A. 3 kg/cm2 B. 9 kg/cm2 C. 12 kg/cm2 D. 16 kg/cm2

D. 16 kg/cm2

157. Air passes thru a nozzle with efficiency of 90%. The velocity of air at the exit is 600 m/s. Find the actual velocity at the exit. A. 382 m/s B. 540 m/s C. 458 m/s D. 568 m/s

D. 568 m/s

150. Air at 10°C and 80 kPa enters a diffuser of a jet engine steadily with a velocity of 200 m/s. The inlet area of diffuser is 0.40 m2. Determine the mass flow rate of air. A. 72.79 kg/s B. 74.79 kg/s C. 76.79 kg/s D. 78.79 kg/s

D. 78.79 kg/s

168. A rigid tank contains 5 kg of an ideal gas at 4 atm and 40°C. Now a valve is opened, and half of mass of the gas is allowed to escape. If the final pressure in the tank is 1.5 atm, the final temperature in the tank is? A. -38°C B. -30°C C. 40°C D. 53°C

A. -38°C

166. The air in an automobile tire with a volume of 0.53 ft3 is at 90°F and 20 psig. Determine the amount of air that must be added to raise the pressure to the recommended value of 30 psig. Assume the atmospheric pressure to be 14.7 psia and the temperature and the volume to remain constant. A. 0.026 lb B. 0.046 lb C. 0.066 lb D. 0.086 lb

A. 0.026 lb

187. A tank contains liquid nitrogen at -190°C is suspended in a vacuum shell by three stainlesssteel rods of 0.80 cm in diameter and 3 meters long with a thermal conductivity of 16.3 W/m2- °C. If the ambient air outside the vacuum shell is 15°C, calculate the magnitude of the conductive heat flow in watts along the support rods. A. 0.168 B. 0.0587 C. 0.182 D. 0.176

A. 0.168

191. Methyl alcohol (CH3OH) is burned with 25% excess air. How much unburned oxygen in kg-moloxygen/kg-molfuel will there be in the products if the combustion is complete? A. 0.35 B. 0.45 C. 0.37 D. 0.65

A. 0.35

155. A heat source at 800 K losses 2000 kJ of heat to a sink at 500 K. Determine the entropy generated during this process. A. 1.5 kJ/K B. 2.5 kJ/K C. -2.5 kJ/K D. 4 kJ/K

A. 1.5 kJ/K

192. A 12 DC electrical motor draws a current of 15 amps. How much work in kJ does this motor produce over a 10-minute period of operation? A. 108.0 B. 129.6 C. 216.0 D. 318.2

A. 108.0

183. In order to cool 1 ton (1000 kg) of water at 20°C in an insulated tank, a person pours 80 kg of ice at -5°C into the water. Determine the final equilibrium temperature in the tank. The melting temperature and the heat of fusion of ice at atmospheric pressure are 0°C and 333.7 kJ/kg, respectively. A. 12.43°C B. 14.43°C C. 16.43°C D. 18.43°C

A. 12.43°C

177. A supply of 50 kg of chicken at 6°C contained in a box is to be frozen to -18°C in a freezer. Determine the amount of heat that needs to be removed. The latent heat of the chicken is 247 kJ/kg, and its specific heat is 3.32 kJ/kg-°C above freezing and 1.77 kJ/kg-°C below freezing. The container box is 1.5 kg, and the specific heat of the box material is 1.4 kJ/kg-°C. Also the freezing temperature of chicken is -2.8°C. A. 15,206.4 kJ B. 50.4 kJ C. 15,156 kJ D. 1,863 kJ

A. 15,206.4 kJ

118. A vacuum pump is used to drain a flooded mine shaft of 20°C 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. 132.33 C. 196.22 D. 171.9

A. 159.30

193. A 4 liter (2-liter per revolution at standard pressure and temperature) spark ignition engine has a compression ratio of 8 and 2200 kJ/kg heat addition by the fluid combustion. Considering a cold air-standard Otto cycle model, how much power will the engine produce when operating at 2500 rpm? A. 166.53 hp B. 73.12 hp C. 97.4 hp D. 148 hp

A. 166.53 hp

144. Carbon dioxide flows through a nozzle with speed of 380 m/s. The entrance condition of nozzle is 250°C and 1200 kPa. Find the stagnation pressure. A. 2,136.34 kPa B. 2,146.34 kPa C. 2,156.34 kPa D. 2,166.34 kPa

A. 2,136.34 kPa

105. Water is flowing in a pipe with radius of 30 cm at a velocity of 5 m/s at the temperature in the pipe. The density and viscosity of the water are as follows: density = 997.9 kg/s viscosity = 1.131 Pa-s. What is the Reynolds number for this situation? A. 2647 B. 96.2 C. 3100 D. 1140

A. 2647

178. Water is being heated in a closed pan on top of a range while being stirred by a paddle wheel. During the process, 30 kJ of heat is transferred to the water, and 5 kJ of heat is lost to the surrounding air. The paddle wheel work amounts to 500 N-m. Determine the final energy of the system if its initial energy is 10 kJ. A. 35.5 kJ B. 40.5 kJ C. 25.5 kJ D. 14.5 kJ

A. 35.5 kJ

128. Assume 8 ft3 of air at 100 psi and 100°F are compressed isothermally to a volume of 2 ft3. For each end state of the process, find the bulk modulus. A. 400 and 100 psi B. 400 and 110 psi C. 400 and 120 psi D. 400 and 130 psi

A. 400 and 100 psi

190. A one cubic meter container contains a mixture of gases composed of 0.02 kg-mol of oxygen and 0.04 kg-mol of helium at a pressure of 220 kPa. What is the temperature of this ideal gas mixture in Kelvin? A. 441 B. 350 C. 400 D. 450

A. 441

169. The pressure of an automobile tire is measured to be 200 kPa (gage) before the trip end 220 kPa (gage) after the trip at a location where the atmospheric pressure is 90 kPa. If the temperature of the air in the tire before the trip is 25°C, the air temperature after the trip is? A. 45.6°C B. 54.8°C C. 27.5°C D. 26.7°C

A. 45.6°C

138. What force is exerted by a water jet, 60 mm in diameter, if it strikes a wall at the rate of 15 m/s? A. 636.17 N B. 442.62 N C. 764.23 N D. 563.34 N

A. 636.17

132. A fan delivers 5.7 m3/s at a static pressure of 5.08 cm of water when operating at a speed of 400 rpm. The power input required is 2.963 kW. If 7.05 m3/s 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

A. 7.77

197. Consider two Carnot heat engines operating in series. The first engine receives heat from the reservoir at 2400 K and rejects the waste heat to another reservoir at temperature T. The second engine receives heat by the first one, convert some of it to work, and rejects the rest to a reservoir at 300 K. If thermal efficiencies of both engines are the same, determine the temperature T. A. 849 K B. 578 K C. 763 K D. 978 K

A. 849 K

165. A spherical balloon with a diameter of 6 m is filled with helium at 20°C and 200 kPa. Determine the mole number. A. 9.28 kmol B. 10.28 kmol C. 11.28 kmol D. 13.28 kmol

A. 9.28 kmol

124. An auditorium seating 1500 people is to be maintained at 80°F dry bulb and 60°F wet bulb temperature when outdoor air is at 91°F dry bulb and 75°F wet bulb. Solar heat load is 110,000 Btu/hr and supply air is at 60°F, determine the amount of supply air. A. 93,229.17 lb/hr B. 83,229.17 lb/hr C. 73,229.17 lb/hr D. 63,229.17 lb/hr

A. 93,229.17 lb/hr

151. Consider a refrigerator whose 40 watts light bulb remains on continuously as a result of a malfunction of the switch. If the refrigerator has a COP of 1.3 and the cost of electricity is 8 cents per kW-hr, determine the increase in the energy consumption of the refrigerator and its cost per year if the switch is not fixed. A. P 49.59 B. P 47.59 C. P 45.59 D. P 43.59

A. P 49.59

137. The type of flow occupying in a 1 cm diameter pipe which water flows at a velocity of 2.50 m/s. Use ν = 1.13x10-6 m2/s for water. A. turbulent B. constant C. laminar D. none of these

A. turbulent

123. The gain of entropy during isothermal nonflow process of 5 lb of air at 60°F is 0.462 Btu/°R. Find the V1/V2. A. 3.85 B. 0.259 C. 1.0 D. 0.296

B. 0.259

146. Air flows through a nozzle with temperature of entrance of 420 K stagnation temperature of 468 K. Find the Mach number. A. 0.744 B. 0.754 C. 0.764 D. 0.774

B. 0.754

111. A two-stage air compressor at 100 kPa and 22°C discharges to 750 kPa. If the intercooler intake is 105°C, determine the value of n. A. 1.400 B. 1.326 C. 1.345 D. 1.288

B. 1.326

180. A 4 m x 5 m x 6 m 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 23°C 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

B. 1.91 kW

173. An aluminum pan whose thermal conductivity is 237 W/m-°C has a flat bottom whose diameter is 20 cm and thickness of 0.4 cm. Heat is transferred steadily to boiling water in the pan through its bottom at a rate of 500 watts. If the inner surface of the bottom of the pan is 105°C, determine the temperature of the surface of the bottom of the pan. A. 95.27°C B. 105.27°C C. 115.27°C D. 125.27°C

B. 105.27°C

167. A rigid tank contains 20 lbm of air at 20 psia and 70°F. More air is added to the tank until the pressure and temperature rise to 35 psia and 90°F, respectively. Determine the amount of air added to the tank. A. 11.73 lb B. 13.73 lb C. 15.73 lb D. 17.73 lb

B. 13.73 lb

101. A rectangular foundation cross-section has a bed plate dimension of 8 ft x 10 ft. The uniform clearance on each side is 1 ft. The height of the foundation is 4.5 ft. If the weight of the steel bar reinforcements needed is ½% of weight of foundation, find the weight of the steel bars. Use concrete density of 2400 kg/m3. A. 173.47 kg B. 183.47 kg C. 163.47 kg D. 153.47 kg

B. 183.47 kg

161. A heat engine receives heat from a source at 1200 K at a rate of 500 kJ/s and rejects the waste heat to a medium at 300 K. The power output of the engine is 180 kW. Determine the irreversibility rate for this process. A. 190 kW B. 195 kW C. 200 kW D. 205 kW

B. 195 kW

179. A classroom that normally contains 40 people is to be air-conditioned with window air- conditioning units of 5 kW cooling capacity. A person at rest may be assumed to dissipate heat at a rate 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 15,000 kJ/hr. If the room is to be maintained at a constant temperature of 21°C, determine the number of window air-conditioning units required. A. 1 units B. 2 units C. 3 units D. 4 units

B. 2 units

134. An empty, open can is 30 cm high with a 15 cm diameter. The can, with the open end down, is pushed under water with a density of 1000 kg/m3. Find the water level in the can when the top of the can is 50 cm below the surface. A. 17.20 cm B. 2.12 cm C. 4.20 cm D. 5.87 cm

B. 2.12 cm

152. A 75 hp motor that has an efficiency of 91% is worn out and is replaced by a high-efficiency motor that has an efficiency of 95.4%. Determine the reduction in heat gain of the room due to higher efficiency under full-load conditions. A. 2.24 kW B. 2.44 kW C. 2.64 kW D. 2.84 kW

B. 2.44 kW

184. A fan is powered by 0.5 hp motor and delivers air at a rate of 85 m3/min. Determine the highest value for the average velocity of air mobilized by the fan. Take the density of air to be 1.18 kg/m3. A. 18.23 m/s B. 21.12 m/s C. 25.34 m/s D. 32.23 m/s

B. 21.12 m/s

160. Consider a large furnace that can supply heat at a temperature of 2000°R at a steady rate of 3000 Btu/s. Determine the exergy of this energy. Assume an environment temperature of 77°F. A. 2305.19 kW B. 2315.19 kW C. 2325.19 kW D. 2335.19 kW

B. 2315.19 kW

185. An Ocean-Thermal Energy Conversion power plant generates 10,000 kW using a warm surface water inlet temperature of 26°C and cold deep-water temperature of 15°C. On the basis of a 3°C drop in the temperature of the warm water and a 3°C rise in the temperature of the cold water due to removal and addition of heat, calculate the power required in kW to pump the cold-deep water to the surface and through the system heat exchanger if the required pumping pressure increase is 12 kPa. Assume a Carnot cycle efficiency and density of cold water to be 100 kg/m3. A. 108 B. 250 C. 146 D. 160

B. 250

175. A 5 cm diameter spherical ball whose surface is maintained at a temperature of 70°C is suspended in the middle of a room at 20°C. If the convection heat transfer coefficient is 15W/m2 -°C and the emissivity of the surface is 0.8, determine the total heat transfer from the ball. A. 23.56 watts B. 32.77 watts C. 9.22 watts D. 43.45 watts

B. 32.77 watts

156. Helium gas is compressed in an adiabatic compressor from an initial state of 14 psia and 50°F to a final temperature of 320°F in a reversible manner. Determine the exit pressure of Helium. A. 38.5 psia B. 40.5 psia C. 42.5 psia D. 44.5 psia

B. 40.5 psia

172. Water is boiler in a pan on a stove at sea level. During 10 minutes of boiling, it is observed that 200 grams of water has evaporated. Then the rate of heat transfer to the water is: A. 0.84 kJ/min B. 45.1 kJ/min C. 41.8 kJ/min D. 53.5 kJ/min

B. 45.1 kJ/min

120. A fan draws 1.42 m3 per second of air at a static pressure of 2.54 cm of water through a duct 300 mm diameter and discharges it through a duct of 275 mm diameter. Determine the static fan efficiency if total fan is 75% and air is measured at 25°C and 760 mm Hg. A. 50.11% B. 53.69% C. 65.67% D. 45.34%

B. 53.69%

113. A water-jacketed air compressor handles 0.343 m3/s of air entering at 96.5 kPa and 21°C and leaving at 480 kPa and 132°C; 10.9 kg/hr of cooling water enters the jacket at 15°C and leaves at 21°C. Determine the compressor brake power. A. 23.163 kW B. 62.65 kW C. 34.44 kW D. 19.33 kW

B. 62.65 kW

159. A windmill with a 12 m diameter rotor is to be installed at a location where the wind is blowing at an average velocity of 10 m/s. Using standard condition of air (1 atm, 25°C), determine the maximum power that can be generated by the windmill. A. 68 kW B. 70 kW C. 72 kW D. 74 kW

B. 70 kW

143. Carbon dioxide flows through a nozzle with a speed of 400 m/s. Compute the dynamic temperature. A. 92.56 K B. 94.56 K C. 96.56 K D. 98.56 K

B. 94.56 K

107. The discharge pressure of an air compressor is 5 times the suction pressure. If volume flow at suction is 0.1 m3/s, 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

B. 98 kPa

121. A water cooler uses 50 lb/hr of melting ice to cool running water from 80°F to 42°F. Based on the inside coil area, Ui = 110 Btu/hr-ft2 -°F. Find the gpm of water cooled. A. 0.10 GPM B. 0.21 GPM C. 0.38 GPM D. 0.45 GPM

C. 0.38 GPM

200. A Carnot cycle operates between the temperature limits of 300 K and 1500 K, and produces 600 kW of net power. The rate of entropy change of the working fluid during heat addition process is? A. 0 B. 0.4 C. 0.5 D. 2.0

C. 0.5

195. The rate of heat transfer to the surroundings from a person at rest is 400 kJ/hr. Suppose that the ventilation system fails in an auditorium containing 120 people and assuming that the energy goes into the air of volume 1500 m3 initially at 300 K and 101 kPa, calculate the rate in °C /min of air temperature change. A. 0.81 B. 0.53 C. 0.63 D. 1.0

C. 0.63

198. An ideal gas mixture consists of 2 kmol of N2 and 6 kmol of CO2. The mass fraction of CO2 is? A. 0.175 B. 0.250 C. 0.825 D. 0.750

C. 0.825

127. A Carnot refrigeration system operates at Tmax/Tmin = 1.5. Find the kW per ton of refrigeration. A. 1.91 B. 2.15 C. 1.76 D. 1.55

C. 1.76

126. A 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

C. 13

148. An insulated rigid tank initially contains 1.5 lb of helium at 80°F and 50 psia. A paddle wheel with power rating of 0.02 hp is operated within the tank for 30 min. Determine the final temperature. A. 159.22°F B. 169.22°F C. 179.22°F D. 189.22°F

C. 179.22°F

170. Water is boiling at 1 atm pressure in a stainless steel pan on an electric range. It is observed that 2 kg of liquid water evaporates in 30 min. The rate of heat transfer to the water is? A. 2.07 kW B. 0.47 kW C. 2.51 kW D. 3.12 kW

C. 2.51 kW

153. A household refrigerator that has a power input of 450 watts and a COP of 2.5 is to cool five large watermelons, 10 kg each, to 8°C. If the watermelons are initially at 20°C, determine how long it will take for the refrigerator to cool them. The watermelons can be treated as water whose specific heat is 4.2 kJ/kg-K. A. 2220 seconds B. 2230 seconds C. 2240 seconds D. 2250 seconds

C. 2240 seconds

135. A cylindrical pipe with water flowing downward at 0.03 m3/s having top diameter of 0.08, bottom diameter of 0.04 m and height of 1.5 m. Find the pressure inside the pipe. A. 154.63 kPa B. 197.93 kPa C. 252.44 kPa D. 243.92 kPa

C. 252.44 kPa

114. A double suction centrifugal pump delivers 20 ft3/s of water at a head of 12 m and running at 650 rpm. What is the specific speed of the pump? A. 5014.12 rpm B. 6453.12 rpm C. 2770.73 rpm D. 9968.73 rpm

C. 2770.73 rpm

102. A steam pipe having a surface temperature of 250°C passes through a room where the temperature is 27°C. The outside diameter of the pipe is 100 mm and emissivity factor is 0.8. Calculate the radiated heat loss for 3 m pipe length. A. 1434.47 W B. 3746.35 W C. 2851.82 W D. 3546.45 W

C. 2851.82 W

106. Compute the amount of condensate formed during a 10 minute warm-up of 180 meter pipe conveys the saturated steam with enthalpy of vaporization, hfg = 1947.8 kJ/kg. The minimum external temperature of pipe is 2°C. The final temperature of pipe is 195°C. The specific heat of pipe material is 0.6 kJ/kg-°C. The specific weight is 28 kg/m. A. 240.69 kg B. 982.45 kg C. 299.64 kg D. 423.45 kg

C. 299.64 kg

154. When a man returns to his wall-sealed house on a summer day, he finds that the house is at 32°C. He returns on the air conditioner which cools the entire house to 20°C in 15 minutes. If COP is 2.5, determine the power drawn by the air conditioner. Assume the entire mass within the house is 800 kg of air for which cv = 0.72 kJ/kg-K, cp = 1.0 kJ/kg-K. A. 1.072 kW B. 2.072 kW C. 3.072 kW D. 4.072 kW

C. 3.072 kW

119. A submersible, multi-stage, centrifugal deep well pump 260 gpm capacity is installed in a well 27 ft 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 ft. 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

C. 3.71

162. A dealer advertises that he has just received a shipment of electric resistance heaters for residential buildings that have an efficiency of 100 percent. Assuming an indoor temperature of 21°C and outdoor temperature of 10°C, determine the second law efficiency of these heaters. A. 8.74% B. 6.74% C. 3.74% D. 4.74%

C. 3.74%

174. For heat transfer purposes, a standing man can be modeled as a 30 cm diameter, 170 cm long vertical cylinder with both the top and bottom surfaces insulated and with the side surface at an average temperature of 34°C. For a convection heat transfer coefficient of 15 W/m2-°C, determine the rate of heat loss from this man by convection in an environment at 20°C. A. 316.46 watts B. 326.46 watts C. 336.46 watts D. 346.46 watts

C. 336.46 watts

158. A 50 kg block of iron casting at 500 K is thrown into a large lake that is at a temperature of 285 K. The iron block eventually reaches thermal equilibrium with the lake water. Assuming average specific heat of 0.45 kJ/kg-K for the iron, determine the entropy generated during this process. A. -12.65 kJ/K B. 16.97 kJ/K C. 4.32 kJ/K D. 6.32 kJ/K

C. 4.32 kJ/K

104. A turbo-charged, 16 cylinder, Vee-type diesel engine has an air consumption of 3,000 kg/hr per cylinder at rated load and speed. This air is drawn in through a filter by a centrifugal compressor directly connected to the exhaust gas turbine. The temperature of the air from the compressor is 135°C and a counter flow air cooler reduces the air temperature to 45°C before it goes to the engine suction header. Cooling water enters the air cooler at 30°C and leaves at 40°C. Calculate the log mean temperature difference. A. 47.23°C B. 87.82°C C. 43.34°C D. 65.24°C

C. 43.34°C

140. Water flowing at the rate of 10 m/s from an orifice at bottom of a reservoir. Find the pressure at the bottom of reservoir. A. 30 kPa B. 40 kPa C. 50 kPa D. 60 kPa

C. 50 kPa

133. A rigid container is closed at one end and measures 8 in diameter by 12 in long. The container is held vertical and is slowly moved downward until the pressure in the container is 17 psia. What will be the depth of the top of the container from the free water surface? A. 42.36 in B. 59.29 in C. 63.69 in D. 69.82 in

C. 63.69 in

194. A simple Rankine cycle produces 40 MW of power, 50 MW of process heated and rejects50 MW of heat to the surroundings. What is the utilization factor of this cogeneration cycle neglecting the pump work? A. 50% B. 60% C. 64% D. 80%

C. 64%

116. The suction pressure of a pump reads 3 in. of mercury vacuum and discharge pressure reads 140 psi is used to deliver 120 gpm of water with specific volume of 0.0163 ft3/lb. Determine the pump work. A. 4.6 kW B. 5.7 kW C. 7.4 kW D. 8.4 kW

C. 7.4 kW

125. In a Brayton cycle that operates between temperature limits of 300 K and 1773 K with k = 1.4, determine the temperature at the end of compression (isentropic) for maximum work of the cycle. A. 780 K B. 690.5 K C. 730 K D. 350 K

C. 730 K

188. An elastic sphere containing gas at 120 kPa has a diameter of 1.0 m. Heating the sphere causes it to expand to a diameter of 1.3 m. During the process the pressure is proportional to the sphere diameter. Calculate the work done by the gas in kJ. A. 41.8 B. 50.6 C. 87.5 D. 35.4

C. 87.5

164. A rigid tank contains 2 kmol of N2 and 6 kmol of CO2 gases at 300 K and 115 MPa. Find the tank volume using the ideal gas equation. A. 7.33 m3 B. 5.33 m3 C. 3.33 m3 D. 1.33 m3

D. 1.33 m3

139. A 300 mm diameter pipe discharges water at a rate of 200 li/s. Point 1 on the pipe has a pressure of 260 kPa and 3.4 m below point 1 is point 2 with a pressure of 300 kPa. Compute the head loss between points 1 and 2. A. 4.29 m B. 2.59 m C. 6.32 m D. 1.87 m

D. 1.87 m

109. An air compressor has a suction volume of 0.35 m3/s at 97 kPa and discharges at 650 kPa. How much power is saved by the compressor if there are two stages? A. 18.27 kW B. 16.54 kW C. 13.86 kW D. 11.58 kW

D. 11.58 kW

129. Predict the pressure of nitrogen gas at T = 200 K and υ = 0.00385 L/g and b = 0.00141 L/g; a= 0.178 L2-kPa/g2. Use Van der Waals equation. A. 15,331 kPa B. 14,331 kPa C. 13,331 kPa D. 12,331 kPa

D. 12,331 kPa

196. An insulated box containing helium gas falls from a balloon 4.5 km above the earth's surface. Calculate the temperature rise in °C of the helium when box hits the ground. A. 15.2 B. 12.6 C. 25.3 D. 14.1

D. 14.1

176. A frictionless piston-cylinder device and a rigid tank contain 1.2 kmol of an ideal gas at the same temperature, pressure and volume. Now heat is transferred, and the temperature of both systems is raised by 15°C. The amount of extra heat that must be supplied to the gas in the cylinder that is maintained at constant pressure is? A. 0 B. 50 kJ C. 100 kJ D. 150 kJ

D. 150 kJ

171. Consider a person standing in a breezy room at 20°C. Determine the total rate of heat transfer from this person if the exposed surface area and the average outer surface temperature of the person are 1.6 m2 and 29°C, respectively, and the convection heat transfer coefficient is 6 W/m2 with emissivity factor of 0.95. A. 86.40 watts B. 81.70 watts C. 198.1 watts D. 168.1 watts

D. 168.1 watts

130. A Francis turbine is to be operated at a speed of 600 rpm and with discharge of 4 m3/s. If r1 = 0.6 m, β = 110°, and the blade height B is 10 cm, what should be the guide vane angle α1 for nonseparating flow condition at the runner entrance? A. 14.4° B. 15.4° C. 16.4° D. 17.4°

D. 17.4°

182. A piston-cylinder device whose piston is resting on top of a set of stops initially contains 0.50 kg of helium gas at 100 kPa and 25°C. The mass of the piston is such that 500 kPa of pressure is required to raise it. How much heat must be transferred to the helium before the piston starts rising? A. 1557.13 kJ B. 1657.13 kJ C. 1757.13 kJ D. 1857.13 kJ

D. 1857.13 kJ

149. A 4 m2 asphalt pavement with emissivity of 0.85 has a surface temperature of 50°C. Find the maximum rate of radiation that can be emitted from the surface. A. 2,068 .32 watts B. 2,078.32 watts C. 2,088.32 watts D. 2,098.32 watts

D. 2,098.32 watts

122. 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°C. 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

D. 2.97

147. Air at 300 K and 200 kPa is heated at constant pressure to 600 K. Determine the change of internal energy. A. 245.58 kJ/kg B. 235.58 kJ/kg C. 225.58 kJ/kg D. 215.58 kJ/kg

D. 215.58 kJ/kg

163. A thermal power plant has a heat rate of 11,363 Btu/kW-hr. Find the thermal efficiency of the plant. A. 34% B. 24% C. 26% D. 30%

D. 30%

186. A plate-type solar energy collector with an absorbing surface covered by a glass plate is to receive an incident radiation of 800 W/m2. The glass plate has a reflectivity of 0.12 and a transmissivity of 0.85. The absorbing surface has an absorptivity of 0.90. The area of the collector is 5 m2. How much solar energy in watts is absorbed by the collector? A. 2500 B. 2880 C. 3510 D. 3060

D. 3060

189. An ideal gas with a molecular weight of 7.1 kg/kg mol is compressed from 600 kPa and 280 K to a final specific volume of 0.5 m3/kg. During the process the pressure varies according to P = 620 + 150υ + 95 υ2 where p is in kPa and υ in m3/kg. Calculate the work of compression in kJ/kg. A. 32.8 B. 28.7 C. 35.6 D. 33.3

D. 33.3

141. Steam flows through a nozzle at 400°C and 1 MPa (h = 3263.9 kJ/kg) with velocity of 300 m/s. Find the stagnation enthalpy. A. 3300 kJ/kg B. 3290 kJ/kg C. 3320 kJ/kg D. 3309 kJ/kg

D. 3309 kJ/kg

103. Brine enters a circulating brine cooler at the rate of 60 m3/hr at -8°C and leaves at -18°C. Specific heat of brine is 1.072 kJ/kg-K and a specific gravity of 1.12. Determine the tons of refrigeration. A. 53.5 TR B. 65.3 TR C. 33.5 TR D. 56.9 TR

D. 56.9 TR

108. The initial condition of air in an air compressor is 98 kPa and 27 °C and discharges air at 450 kPa. The bore and stroke are 355 mm and 381 mm, respectively with percent clearance of 8% running at 300 rpm. Find the volume of air at suction. A. 541.62 m3/hr B. 551.62 m3/hr C. 561.62 m3/hr D. 571.62 m3/hr

D. 571.62 m3 /hr

181. A student living in a 4 m x 6 m x 6 m 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 15°C in the morning when she leaves. A. 28.13°C B. 38.13°C C. 48.13°C D. 58.13°C

D. 58.13°C

136. Determine the size of pipe which will deliver 8 liters of medium oil (ν = 6.10x10-6 m2/s) assuming laminar flow conditions. A. 622 mm B. 754 mm C. 950 mm D. 835 mm

D. 835 mm

117. A submersible pump delivers 350 gpm of water to a height of 5 ft from the ground. The pump where installed 150 ft below the ground level and a drawdown 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

D. 9.27 kW

131. The total head of fan is 187 m and has a static pressure of 210 mm of water gage, what is the velocity of air flowing if the density of air is 1.15 kg/m3? A. 6.85 m/s B. 3.45 m/s C. 4.39 m/s D. 9.28 m/s

D. 9.28 m/s

115. Determine the number of stages needed for a centrifugal pump if it is used to deliver 400 gal/min of water and pump power of 15 hp. Each impeller develops a head of 30 ft. A. 6 B. 4 C. 5 D. 7

c. 5