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free/or 0.5$ |
| 55563 | A square hole 8.00 cm along each side is cut in a sheet of copper. (a) Calculate the change in the area of this hole if the temperature of the sheet is increased by 50.0 K. (b) Does this change represent an increase or a decrease in the area enclosed by the hole? |
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| 55564 | A spherical balloon of volume 4 000 cm3 contains helium at an (inside) pressure of 1.20 X 105 Pa. How many moles of helium are in the balloon if the average kinetic energy of the helium atoms is 3.60 % 10-22J? |
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| 55565 | Speedy Sue, driving at 30.0 m/s, enters a one-lane tunnel. She then observes a slow-moving van 155 m ahead traveling at 5.00 m/s. Sue applies her brakes but can accelerate only at - 2.00 m/s 2 because the road is wet. Will there be a collision? If yes, determine how far into the tunnel and at what time the collision occurs. If no, determine the distance of closest approach between Sue’s car and the van |
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| 55566 | A speedboat moving at 30.0 m/s approaches a no-wake buoy marker 100m ahead. The pilot slows the boat with a constant acceleration of - 3.50 m/s2 by reducing the throttle.
(a) How long does it take the boat to reach the buoy?
(b) What is the velocity of the boat when it reaches the buoy? |
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| 55567 | Solve Example 2.8, “Watch out for the Speed Limit!” by a graphical method. On the same graph plot position versus time for the car and the police officer, from the intersection of the two curves read the time at which the trooper overtakes the car |
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| 55568 | A solar cooker consists of a curved reflecting surface that concentrates sunlight onto the object to be warmed (Fig. P20.63), the solar power per unit area reaching the Earth’s surface at the location is 600 W/m2. The cooker faces the Sun and has a diameter of 0.600 m. Assume that 40.0% of the incident energy is transferred to 0.500 L of water in an open container, initially at 20.0°C. How long does it take to completely boil away the water? (Ignore the heat capacity of the container.) |
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| 55569 | Smokin’! A pitcher throws a 0.142-kg baseball at 47.2 m/s (Fig. P21.62). As it travels 19.4 m, the ball slows to a speed of 42.5 m/s because of air resistance. Find the change in temperature of the air through which it passes. To find the greatest possible temperature change, you may make the following assumptions: Air has a molar specific heat of CP = 7R / 2 and an equivalent molar mass of 28.9 g/mol. The process is so rapid that the cover of the baseball acts as thermal insulation, and the temperature of the ball itself does not change. A change in temperature happens initially only for the air in a cylinder 19.4 m in length and 3.70 cm in radius. This air is initially at 20.0°C. |
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| 55570 | A small metal crucible is taken from a 200°C oven and immersed in a tub full of water at room temperature (this process is often referred to as quenching). What is the approximate final equilibrium temperature? |
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| 55571 | Show that the mean free path for the molecules of an ideal gas is |
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| 55572 | Setting a new world record in a 100-m race, Maggie and Judy cross the finish line in a dead heat, both taking 10.2 s. Accelerating uniformly, Maggie took 2.00 s and Judy 3.00 s to attain maximum speed, which they maintained for the rest of the race.
(a) What was the acceleration of each sprinter?
(b) What were their respective maximum speeds?
(c) Which sprinter was ahead at the 6.00-s mark, and by how much? |
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| 55573 | Secretariat won the Kentucky Derby with times for successive quarter-mile segments of 25.2 s, 24.0 s, 23.8, and 23.0 s.
(a) Find his average speed during each quarter-mile segment.
(b) Assuming that Secretariat’s instantaneous speed at the finish line was the same as the average speed during the final quarter mile; find his average acceleration for the entire race. (Horses in the Derby start from rest.) |
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| 55574 | A sealed cubical container 20.0 cm on a side contains three times Avogadro’s number of molecules at a temperature of 20.0°C. Find the force exerted by the gas on one of the walls of the container. |
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| 55575 | (a) Sand dunes in a desert move over time as sand is swept up the windward side to settle in the lee side. Such “walking” dunes have been known to walk 20 feet in a year and can travel as much as 100 feet per year in particularly windy times. Calculate the average speed in each case in m/s.
(b) Fingernails grow at the rate of drifting continents, on the order of 10 mm/yr. Approximately how long did it take for North America to separate from Europe, a distance of about 3 000 mi? |
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| 55576 | A sample of monatomic ideal gas occupies 5.00 L at atmospheric pressure and 300 K (point A in Figure P21.67). It is heated at constant volume to 3.00 atm (point B).
Then it is allowed to expand isothermally to 1.00 atm (point C) and at last compressed isobarically to its original state.
(a) Find the number of moles in the sample.
(b) Find the temperature at points B and C and the volume at point C.
(c) Assuming that the molar specific heat does not depend on temperature, so that Eint # 3nRT/2, find the internal energy at points A, B, and C.
(d) Tabulate P, V, T, and Eint for the states at points A, B, and C.
(e) Now consider the processes A →B, B→ C, and C→ A. Describe just how to carry out each process experimentally.
(f) Find Q, W, and ΔEint for each of the processes.
(g) For the whole cycle A→ B→ C→ A find Q, W, and ΔEint |
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| 55577 | A sample of an ideal gas is in a vertical cylinder fitted with a piston. As 5.79 kJ of energy is transferred to the gas by heat to raise its temperature, the weight on the piston is adjusted so that the state of the gas changes from point A to point B along the semicircle shown in Figure P20.33. Find the change in internal energy of the gas. |
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| 55578 | A sample of ideal gas is expanded to twice its original volume of 1.00 m3 in a quasi-static process for which P =αV 2, with α = 5.00 atm/m6, as shown in Figure P20.23. How much work is done on the expanding gas? |
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| 55579 | A sample of an ideal gas goes through the process shown in Figure P20.32. From A to B, the process is adiabatic; from B to C, it is isobaric with 100 kJ of energy entering the system by heat. From C to D, the process is isothermal; from D to A, it is isobaric with 150 kJ of energy leaving the system by heat. Determine the difference in internal energy E int, B - E int A- |
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| 55580 | A sample of dry air that has a mass of 100.00 g, collected at sea level, is analyzed and found to consist of the following gases: Nitrogen (N2) = 75.52 g Oxygen (O2) = 23.15 g Argon (Ar) = 1.28 g Carbon dioxide (CO2) # 0.05 g Plus trace amounts of neon, helium, methane, and other gases. (a) Calculate the partial pressure of each gas when the pressure is 1.013 X 105 Pa. (b) Determine the volume occupied by the 100-g sample at a temperature of 15.00°C and a pressure of 1.00 atm. What is the density of the air for these conditions? (c) What is the effective molar mass of the air sample? |
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| 55581 | A sample consisting of n mol of an ideal gas undergoes a reversible isobaric expansion from volume Vi to volume 3Vi. Find the change in entropy of the gas by calculating |
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| 55582 | Rubber has a negative average coefficient of linear expansion. What happens to the size of a piece of rubber as it is warmed? |
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