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Condition |
free/or 0.5$ |
| 55583 | A room of volume V contains air having equivalent molar mass M (in g/mol). If the temperature of the room is raised from T1 to T2, what mass of air will leave the room? Assume that the air pressure in the room is maintained at P0. |
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| 55584 | A rock is dropped from rest into a well. The well is not really 16 seconds deep, as in Figure P2.70.
(a) The sound of the splash is actually heard 2.40 s after the rock is released from rest. How far below the top of the well is the surface of the water? The speed of sound in air (at the ambient temperature) is 336 m/s.
(b) What If? If the travel time for the sound is neglected, what percentage error is introduced when the depth of the well is calculated? |
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| 55585 | A rigid tank of small mass contains 40.0 g of argon, initially at 200°C and 100 kPa. The tank is placed into a reservoir at 0°C and allowed to cool to thermal equilibrium. (a) Calculate the volume of the tank. (b) Calculate the change in internal energy of the argon. (c) Calculate the energy transferred by heat. (d) Calculate the change in entropy of the argon. (e) Calculate the change in entropy of the constant- temperature bath. |
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| 55586 | Repeat the procedure used to construct Table 22.1
(a) For the case in which you draw three marbles from your bag rather than four and
(b) For the case in which you draw five rather than four. |
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| 55587 | A refrigerator maintains a temperature of 0°C in the cold compartment with a room temperature of 25.0°C. It removes energy from the cold compartment at the rate of 8 000 kJ/h.
(a) What minimum power is required to operate the refrigerator?
(b) The refrigerator exhausts energy into the room at what rate? |
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| 55588 | A refrigerator has a coefficient of performance of 3.00. The ice tray compartment is at -20.0°C, and the room temperature is 22.0°C. The refrigerator can convert 30.0 g of water at 22.0°C to 30.0 g of ice at - 20.0°C each minute. What input power is required? Give your answer in watts |
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| 55589 | A refrigerator has a coefficient of performance equal to 5.00. The refrigerator takes in 120 J of energy from a cold reservoir in each cycle. Find
(a) The work required in each cycle and
(b) The energy expelled to the hot reservoir. |
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| 55590 | A professional physics teacher drops one marshmallow into a flask of liquid nitrogen, waits for the most energetic boiling to stop, fishes it out with tongs, shakes it off, pops it into his mouth, chews it up, and swallows it. Clouds of ice crystals issue from his mouth as he crunches noisily and comments on the sweet taste. How can he do this without injury? Caution: Liquid nitrogen can be a dangerous substance and you should not try this yourself. The teacher might be badly injured if he did not shake it off, if he touched the tongs to a tooth, or if he did not start with a mouthful of saliva. |
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| 55591 | This problem can help you to think about the size of molecules. In the city of Beijing a restaurant keeps a pot of chicken broth simmering continuously. Every morning it is topped up to contain 10.0 L of water, along with a fresh chicken, vegetables, and spices. The soup is thoroughly stirred. The molar mass of water is 18.0 g/mol.
(a) Find the number of molecules of water in the pot.
(b) During a certain month, 90.0% of the broth was served each day to people who then emigrated immediately. Of the water molecules in the pot on the first day of the month, when was the last one likely to have been ladled out of the pot?
(c) The broth has been simmering for centuries, through wars, earthquakes, and stove repairs. Suppose the water that was in the pot long ago has thoroughly mixed into the Earth’s hydrosphere, of mass 1.32 X 1021 kg. How many of the water molecules originally in the pot are likely to be present in it again today? |
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| 55592 | Prepare a table like Table 22.1 for the following occurrence. You toss four coins into the air simultaneously and then record the results of your tosses in terms of the numbers of heads and tails that result. For example, HHTH and HTHH are two possible ways in which three heads and one tail can be achieved.
(a) On the basis of your table, what is the most probable result of a toss? In terms of entropy,
(b) What is the most ordered state and
(c) What is the most disordered state? |
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| 55593 | A power transistor is a solid-state electronic device. Assume that energy entering the device at the rate of 1.50 W by electrical transmission causes the internal energy of the device to increase. The surface area of the transistor is so small that it tends to overheat. To prevent overheating, the transistor is attached to a larger metal heat sink with fins. The temperature of the heat sink remains constant at 35.0°C under steady-state conditions. The transistor is electrically insulated from the heat sink by a rectangular sheet of mica measuring 8.25 mm by 6.25 mm, and 0.085 2 mm thick. The thermal conductivity of mica is equal to 0.075 3 W/m . °C. What is the operating temperature of the transistor? |
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| 55594 | A power plant operates at a 32.0% efficiency during the summer when the sea water used for cooling is at 20.0°C. The plant uses 350°C steam to drive turbines. If the plant’s efficiency changes in the same proportion as the ideal efficiency, what would be the plant’s efficiency in the winter, when the sea water is 10.0°C? |
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| 55595 | A power plant, having a Carnot efficiency, produces electric power from turbines that take in energy from steam at temperature Th and discharge energy at temperature Tc through a heat exchanger into a flowing river. The water downstream is warmer by ΔT due to the output of the power plant. Determine the flow rate of the river. |
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| 55596 | A power plant, having a Carnot efficiency, produces 1 000 MW of electrical power from turbines that take in steam at 500 K and reject water at 300 K into a flowing river. The water downstream is 6.00 K warmer due to the output of the power plant. Determine the flow rate of the river. |
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| 55597 | A position-time graph for a particle moving along the x axis is shown in Figure P2.7.
(a) Find the average velocity in the time interval t = 1.50 s to t = 4.00 s
(b) Determine the instantaneous velocity at t = 2.00 s by measuring the slope of the tangent line shown in the graph
(c) At what value of t is the velocity zero? |
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| 55598 | A popular brand of cola contains 6.50 g of carbon dioxide dissolved in 1.00 L of soft drink. If the evaporating carbon dioxide is trapped in a cylinder at 1.00 atm and 20.0°C, what volume does the gas occupy? |
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| 55599 | A pond of water at 0°C is covered with a layer of ice 4.00 cm thick. If the air temperature stays constant at &10.0°C, how long does it take for the ice thickness to increase to 8.00 cm? |
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| 55600 | Pioneers stored fruits and vegetables in underground cellars. Discuss the advantages of this choice for a storage site. |
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| 55601 | A piece of paper is wrapped around a rod made half of wood and half of copper. When held over a flame, the paper in contact with the wood burns but the half in contact with the metal does not. Explain. |
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| 55602 | A piece of copper is dropped into a beaker of water. If the water’s temperature rises, what happens to the temperature of the copper? Under what conditions are the water and copper in thermal equilibrium? |
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