| № |
Condition |
free/or 0.5$ |
| 55643 | Just 9.00 g of water is placed in a 2.00-L pressure cooker and heated to 500°C. What is the pressure inside the container? |
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| 55644 | Jules Verne in 1865 suggested sending people to the Moon by firing a space capsule from 220-m-long cannon with a launch speed of 10.97 km/s. What would have been the unrealistically large acceleration experienced by the space travelers during launch? Compare your answer with the free-fall acceleration 9.80 m/s2. |
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| 55645 | A jet plane lands with a speed of 100 m/s and can accelerate at a maximum rate of - 5.00 m/s2 as it comes to rest.
(a) From the instant the plane touches the runway, what is the minimum time interval needed before it can come to rest?
(b) Can this plane land on a small tropical island airport where the runway is 0.800 km long? |
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| 55646 | It is possible to shoot an arrow at a speed as high as100 m/s.
(a) If friction is neglected, how high would an arrow launched at this speed rise if shot straight up?
(b) How long would the arrow be in the air? |
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| 55647 | Is it possible to convert internal energy to mechanical energy? Explain with examples. |
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| 55648 | Is it possible to construct a heat engine that creates no thermal pollution? What does this tell us about environmental considerations for an industrialized society? |
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| 55649 | Is it possible for two objects to be in thermal equilibrium if they are not in contact with each other? Explain |
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| 55650 | Is it possible for the velocity and the acceleration of an object to have opposite signs? If not, state a proof. If so, give an example of such a situation and sketch a velocity–time graph to prove your point. |
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| 55651 | An iron plate is held against an iron wheel so that a kinetic friction force of 50.0 N acts between the two pieces of metal. The relative speed at which the two surfaces slide over each other is 40.0 m/s.
(a) Calculate the rate at which mechanical energy is converted to internal energy.
(b) The plate and the wheel each have a mass of 5.00 kg, and each receives 50.0% of the internal energy. If the system is run as described for 10.0 s and each object is then allowed to reach a uniform internal temperature, what is the resultant temperature increase? |
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| 55652 | Inspecting the magnitudes of CV and CP for the diatomic and polyatomic gases in Table 21.2, we find that the values increase with increasing molecular mass. Give a qualitative explanation of this observation. |
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| 55653 | Inside the wall of a house, an L-shaped section of hot-water pipe consists of a straight horizontal piece 28.0 cm long, an elbow, and a straight vertical piece 134 cm long (Figure P19.14). A stud and a second-story floorboard hold stationary the ends of this section of copper pipe. Find the magnitude and direction of the displacement of the pipe elbow when the water flow is turned on, raising the temperature of the pipe from 18.0°C to 46.5°C. |
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| 55654 | An inquisitive physics student and mountain climber climbs a 50.0-m cliff that overhangs a calm pool of water. He throws two stones vertically downward, 1.00 s apart, and observes that they cause a single splash. The first stone has an initial speed of 2.00 m/s.
(a) How long after release of the first stone do the two stones hit the water?
(b) What initial velocity must the second stone have if they are to hit simultaneously?
(c) What is the speed of each stone at the instant the two hit the water? |
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| 55655 | An inflated rubber balloon filled with air is immersed in a flask of liquid nitrogen that is at 77 K. Describe what happens to the balloon, assuming that it remains flexible while being cooled. |
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| 55656 | An incandescent light bulb contains a volume V of argon at pressure Pi. The bulb is switched on and constant power "is transferred to the argon for a time interval "t.
(a) Show that the pressure Pf in the bulb at the end of this process is Pf = Pi [1 + (PΔtR) / (PiVCV)].
(b) Find the pressure in a spherical light bulb 10.0 cm in diameter 4.00 s after it is switched on, given that it has initial pressure 1.00 atm and that 3.60W of power is transferred to the gas. |
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| 55657 | In view of the fact that hot air rises, why does it generally become cooler as you climb a mountain? (Note that air has low thermal conductivity.) |
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| 55658 | In an ultra-high-vacuum system, the pressure is measured to be 1.00 X 10-10 torr (where 1 torr = 133 Pa). Assuming the molecular diameter is 3.00 % 10-10 m, the average molecular speed is 500 m/s, and the temperature is 300 K, find
(a) The number of molecules in a volume of 1.00 m3,
(b) The mean free path of the molecules, and
(c) The collision frequency. |
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| 55659 | In the Daytona 500 auto race, a Ford Thunderbird and a Mercedes Benz are moving side by side down a straightaway at 71.5 m/s. The driver of the Thunderbird realizes he must make a pit stop, and he smoothly slows to a stop over a distance of 250 m. He spends 5.00 s in the pit and then accelerates out, reaching his previous speed of 71.5 m/s after a distance of 350 m. At this point, how far has the Thunderbird fallen behind the Mercedes Benz, which has continued at a constant speed? |
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| 55660 | In a tank full of oxygen, how many molecular diameters d (on average) does an oxygen molecule travel (at 1.00 atm and 20.0°C) before colliding with another O2 molecule? (The diameter of the O2 molecule is approximately 3.60 X 10-10 m.) |
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| 55661 | In state-of-the-art vacuum systems, pressures as low as 10-9 Pa are being attained. Calculate the number of molecules in a 1.00-m3 vessel at this pressure if the temperature is 27.0°C. |
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| 55662 | In solar ponds constructed in Israel, the Sun’s energy is concentrated near the bottom of a salty pond. With the proper layering of salt in the water, convection is prevented, and temperatures of 100°C may be reached. Can you estimate the maximum efficiency with which useful energy can be extracted from the pond? |
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