| № |
Condition |
free/or 0.5$ |
| 55243 | 2.0 mol of an ideal gas expands isothermally from a volume of 20 L to 40 L at 20 oC.
(a) The work done by the gas is (1) positive, (2) negative, (3) zero. Explain.
(b) What is the magnitude of the work? |
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| 55244 | 2.0 kg of ice melts completely into liquid water at 0 oC.
(a) The change in entropy of the ice (water) in this process is (1) positive, (2) zero, (3) negative. Explain.
(b) What is the change in entropy of the ice (water)? |
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| 55245 | 131I is given to a patient for use in a diagnostic procedure on her thyroid. What percentage of the 131I sample remains after exactly one day, assuming that all of the 131I is retained in the patient’s thyroid gland? (Answer to three significant figures.) |
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| 55246 | You throw a stone vertically upward with an initial speed of 6.0 m/s from a third-story office window. If the window is 12 m above the ground, find
(a) The time the stone is in flight and
(b) The speed of the stone just before it hits the ground. |
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| 55247 | You can perform a popular trick by dropping a dollar bill (lengthwise) through the thumb and forefinger of a fellow student. Tell your fellow student to grab the dollar bill as fast as possible, and he or she can have the dollar if able to catch it. (The length of a dollar is 15.7 cm, and the average human reaction time is about 0.20 s.) Is this proposal a good deal? Justify your answer. |
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| 55248 | You are sailing a radio-controlled model powerboat on a perfectly circular pool of water. The boat travels at a constant 0.500 m/s. It takes 30.0 s to make the trip from one side of the pool, through the center, to the other side.
(a) How long would it take the boat to travel completely around the edge of the pool?
(b) If the pool is uniformly 1.50 m deep, how many gallons of water does it hold? |
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| 55249 | Work this exercise by the two given procedures as directed, commenting on and explaining any difference in the answers. Use your calculator for the calculations. Compute ρ = mv, where v = x/t, given x = 8.5 m, t = 2.7s, and m = 0.66kg.
(a) First compute v and then p.
(b) Compute ρ = mx/t without an intermediate step.
(c) Are the results the same? If not, why? |
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| 55250 | What size cube (in centimeters) would have a volume equal to that of a quart? |
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| 55251 | What is the magnitude of the displacement of a car that travels half a lap along a circle that has a radius of 150 m? How about when the car travels a full lap? |
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| 55252 | What is the acceleration for each graph segment in Fig. 2.23? Describe the motion of the object over the total time interval. |
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| 55253 | Water is sold in pint bottles. What is the mass of the water in a full bottle? |
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| 55254 | Two students go into Tony’s Pizza Palace and order a 12-in. (diameter) pizza. Shortly thereafter, the waitress brings an 8-in. pizza special. She explains that the 12-in. pizza was given to someone else by mistake and they could have the 8-in. now and she would bring another 8-in. shortly to make up for the missing 12-in. pizza. Was this a good deal? |
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| 55255 | Two separate seismograph stations receive indication of an earthquake in the form of a wave traveling to them in a straight line from the epicenter and shaking the ground at their locations. Station B is 50 km due east of station A. The epicenter is located due north of station A and 30o north of due west from station B.
(a) Draw a sketch and use it to determine the distance from the epicenter to A.
(b) Determine the distance from the epicenter to B.
(c) Station C is located an additional 20 km east of B. At what angle does C report the direction of the epicenter to be? |
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| 55256 | Two runners approaching each other on a straight track have constant speeds of 4.50 m/s and 3.50 m/s, respectively, when they are 100 m apart (Fig. 2.22).
How long will it take for the runners to meet, and at what position will they meet if they maintain these speeds? |
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| 55257 | Two identical cars capable of accelerating at 3.00 m/s2 are racing on a straight track with running starts. Car A has an initial speed of 2.50 m/s; car B starts with speed of 5.00 m/s.
(a) What is the separation of the two cars after 10 s?
(b) Which car is moving faster after 10 s? |
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| 55258 | Two chains of length 1.0 m are used to support a lamp, as shown in Fig. 1.21. The distance between the two chains along the ceiling is 1.0 m. What is the vertical distance from the lamp to the ceiling? |
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| 55259 | Tony’s Pizza Palace sells a medium 9.0-in. (diameter) pizza for $ 7.95 and a large 12- in. pizza for $ 13.50. Which pizza is the better buy? |
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| 55260 | To go to a football stadium from your house, you first drive 1000 m north, then 500 m west, and finally 1500 m south.
(a) Relative to your home, the football stadium is (1) north of west, (2) south of east, (3) north of east, (4) south of west.
(b) What is the straight-line distance from your house to the stadium? |
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| 55261 | The units for pressure (p) in terms of SI base units are known to be kb/m∙s2. For a physics class assignment, a student derives an expression for the pressure exerted by the wind on a wall in terms of the air density (ρ) and wind speed (v) and her result is p = ρv2. Use SI unit analysis to show that her result is dimensionally consistent. Does this prove that this relationship is physically correct? |
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| 55262 | The top of a rectangular table measures 1.245 m by 0.760 m.
(a) The smallest division on the scale of the measurement instrument is (1) m, (2) cm, (3) mm. Why?
(b) What is the area of the tabletop? |
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