A double-glazed window consists of two panes of glass, each of thickness
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Fundamentals of Heat and Mass Transfer
- Answer is RA = 12.50 KN and RB = 0.50 KNarrow_forwardShape factor for a cylinder whose length equals its diameter is 1.5 B. 0.5 1.0 D. 2.0arrow_forwardA thermometer is being designed for a process in which the temperature varies from 0 to 180 °C; from experience it is known that the process temperature, when it gets out of control, reaches up to 240 ° C. Considering that only the bulb is in contact with the part inside the equipment, what should be the volume of the safety vial? It is known that the bulb has a length of 1.2 cm and a diameter of 0.5 cm; the capillary has a length of 20 cm and the scale of the thermometer is -10 to 190 ° C. Consider that the coefficient of volumetric expansion for mercury is 1.82×10−4 ° C− 1arrow_forward
- A monatomic ideal gas initially fills a V0 = 0.45 m3 container at P0 = 85 kPa. The gas undergoes an isobaric expansion to V1 = 0.75 m3. Next it undergoes an isovolumetric cooling to its initial temperature T0. Finally it undergoes an isothermal compression to its initial pressure and volume. (a). Calculate the work done by the gas, W1, in kilojoules, during the isobaric expansion (first process). (b). Calculate the heat absorbed Q1, in kilojoules, during the isobaric expansion (first process). (c) Calculate the heat absorbed Q2, in kilojoules, during the isovolumetric cooling (second process). (d) Calculate the change in internal energy by the gas, ΔU2, in kilojoules, during the isovolumetric cooling (second process). (e) Calculate the work done by the gas, W3, in kilojoules, during the isothermal compression (third process). (f) Calculate the heat absorbed Q3, in kilojoules, during the isothermal compressions (third process).arrow_forwardWhich of the following statement (s) are correct? I) Heat transfer is by conduction in opaque solids II) Heat transfer is by conduction and convection in semitransparent solids III) Heat transfer is by conduction in flowing liquids IV) Heat transfer is by conduction and radiation in still gases V) Heat transfer is by convection and radiation in flowing gases VI) Heat transfer is by convection in vacuum a. I, IV and VI b. I, IV and V c. I, II and V d. II, IV and VI e. II, III and Varrow_forwardPressure cookers, in general, maintain a gage pressure of 2 atm (or 3 atm absolute) inside. Therefore, pressure cookers cook at a temperature of about 133°C instead of 100°C, cutting the cooking time by as much as 70 percent while minimizing the loss of nutrients. The newer pressure cookers use a spring valve with several pressure settings rather than a weight on the cover. A certain pressure cooker has a volume of 6 L and an operating pressure of 75 kPa gage. Initially, it contains 1 kg of water. Heat is supplied to the pressure cooker at a rate of 500 W for 30 min after the operating pressure is reached. Assuming an atmospheric pressure of 100 kPa, determine the temperature at which cooking takes place.arrow_forward
- Pressure cookers, in general, maintain a gage pressure of 2 atm (or 3 atm absolute) inside. Therefore, pressure cookers cook at a temperature of about 133°C instead of 100°C, cutting the cooking time by as much as 70 percent while minimizing the loss of nutrients. The newer pressure cookers use a spring valve with several pressure settings rather than a weight on the cover. A certain pressure cooker has a volume of 6 L and an operating pressure of 75 kPa gage. Initially, it contains 1 kg of water. Heat is supplied to the pressure cooker at a rate of 500 W for 30 min after the operating pressure is reached. Assuming an atmospheric pressure of 100 kPa, determine the amount of water left in the pressure cooker at the end of the process.arrow_forward3. 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 of about 360 kJ/h. There are 10 light bulbs in the room, each with a rating of 100 W. The rate of heat transfer to the classroom through the walls and the windows is estimated to be 15,000 kJ/h. If the room air is to be maintained at a constant temperature of 210C, determine the number of window air-conditioning units required. draw a figure also, and explain each step by step solution.arrow_forwardA cylindrical vessel with a diameter of 8 inches and 5 feet long contained acetylene at 300 psi gauge and 82°F. After some amount of acetylene was used, the pressure was reduced to 190 psi gauge and the temperature was 74°F. The gas constant of acetylene is 59.35 ft-lbf/lbm-°R. Determine the following: What is the initial mass in lbm of the acetylene inside the vessel What proportion in percentage of acetylene was used? What volume in ft3 would the used acetylene occupy at 30 psig and 80°F?arrow_forward
- THE PRESSURE IN THE SUBTANCE DRASTICALLY DECREASE FROM 354 TO 21 POUNDS PER SUARE INCHES (PSI), THE HEAT ENERGY OF THE OPEN SYSTEM REDUCES 555BTU/LB, AND THE VOLUME INCREASES FROM 1 TO 10FT^3/LB. (A) DETERMINE THE WORK PER LB. UNITS:BTU/LB * (B) DETERMINE THE WORK IN HP (HORSE POWER) FOR 10LB PER MIN. (1HP = 42.4BTU/MIN). UNITS:HParrow_forward3. Two spherical vessels of different sizes contain the same gas and are connected by means of a pipe with a valve. Sphere A has a diameter of 5 foot at the given pressure gauge of 50 kgf/cm2. Sphere B contains the same gas at 20 kgf/cm2 gauge. The valve is opened and when the properties have been determined, it is found out that the gauge pressure is 36 kgf/cm2. The temperature at the two vessels before and after opening the valve is maintained at 21.1oC. If the gas inside the sphere is ammonia, find the following: -The temperature at sphere B in Farrow_forward3. Two spherical vessels of different sizes contain the same gas and are connected by means of a pipe with a valve. Sphere A has a diameter of 5 foot at the given pressure gauge of 50 kgf/cm2. Sphere B contains the same gas at 20 kgf/cm2 gauge. The valve is opened and when the properties have been determined, it is found out that the gauge pressure is 36 kgf/cm2. The temperature at the two vessels before and after opening the valve is maintained at 21.1oC. If the gas inside the sphere is ammonia, find the following: -The volume of sphere A in in3 -The pressure of sphere A in psia -The temperature of sphere A in R -The pressure at sphere B in psiaarrow_forward
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