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| 55463 | (a) Use the data in Problem 1 to construct a smooth graph of position versus time.
(b) By constructing tangents to the x (t) curve, find the instantaneous velocity of the car at several instants.
(c) Plot the instantaneous velocity versus time and, from this, determine the average acceleration of the car.
(d) What was the initial velocity of the car? |
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| 55464 | Use nodal analysis to find Io and I1 in the circuit shown. |
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| 55465 | Updrafts of air are familiar to all pilots and are used to keep non-motorized gliders aloft. What causes these currents? |
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| 55466 | Two thermally insulated vessels are connected by a narrow tube fitted with a valve that is initially closed. One vessel, of volume 16.8 L, contains oxygen at a temperature of 300 K and a pressure of 1.75 atm. The other vessel, of volume 22.4 L, contains oxygen at a temperature of 450 K and a pressure of 2.25 atm. When the valve is opened, the gases in the two vessels mix, and the temperature and pressure become uniform throughout. (a) What is the final temperature? (b) What is the final pressure? |
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| 55467 | Two speeding lead bullets, each of mass 5.00 g, and at temperature 20.0°C, collide head-on at speeds of 500 m/s each. Assuming a perfectly inelastic collision and no loss of energy by heat to the atmosphere, describe the final state of the two-bullet system. |
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| 55468 | Two identically constructed objects, surrounded by thermal insulation, are used as energy reservoirs for a Carnot engine. The finite reservoirs both have mass m and specific heat c. They start out at temperatures Th and Tc, where Th > Tc, (a) Show that the engine will stop working when the final temperature of each object is (Th Tc) 1/2. (b) Show that the total work done by the Carnot engine is |
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| 55469 | Two identical cylinders at the same temperature each contain the same kind of gas and the same number of moles of gas. If the volume of cylinder A is three times greater than the volume of cylinder B, what can you say about the relative pressures in the cylinders? |
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| 55470 | Two identical cups both at room temperature are filled with the same amount of hot coffee. One cup contains a metal spoon, while the other does not. If you wait for several minutes, which of the two will have the warmer coffee, which energy transfer process explains your answer? |
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| 55471 | Two gases in a mixture diffuse through a filter at rates proportional to the gases’ rms speeds.
(a) Find the ratio of speeds for the two isotopes of chlorine, 35Cl and 37Cl, as they diffuse through the air.
(b) Which isotope moves faster? |
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| 55472 | Two concrete spans of a bridge of length L are placed end to end so that no room is allowed for expansion (Fig. P19.61a). If a temperature increase of ΔT occurs, what is the height y to which the spans rise when they buckle (Fig P19.61b) |
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| 55473 | Two concrete spans of a 250-m-long bridge are placed end to end so that no room is allowed for expansion (Fig. P19.61a). If a temperature increase of 20.0°C occurs, what is the height y to which the spans rise when they buckle (Fig P19.61b)? |
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| 55474 | Two cars are moving in the same direction in parallel lanes along a highway. At some instant, the velocity of car A exceeds the velocity of car B. Does this mean that the acceleration of A is greater than that of B? Explain. |
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| 55475 | Two Carnot engines have the same efficiency. One engine runs in reverse as a heat pump, and the other runs in reverse as a refrigerator. The coefficient of performance of the heat pump is 1.50 times the coefficient of performance of the refrigerator. Find
(a) The coefficient of performance of the refrigerator,
(b) The coefficient of performance of the heat pump, and
(c) The efficiency of each heat engine. |
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| 55476 | Twenty particles, each of mass m and confined to a volume V, have various speeds: two have speed v; three have speed 2v; five have speed 3v; four have speed 4v; three have speed 5v; two have speed 6v ; one has speed 7v. Find
(a) The average speed,
(b) The rms speed,
(c) The most probable speed,
(d) The pressure the particles exert on the walls of the vessel, and
(e) The average kinetic energy per particle. |
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| 55477 | A truck on a straight road starts from rest, accelerating at 2.00 m/s2 until it reaches a speed of 20.0 m/s. Then the truck travels for 20.0 s at constant speed until the brakes are applied, stopping the truck in a uniform manner in an additional 5.00 s.
(a) How long is the truck in motion?
(b) What is the average velocity of the truck for the motion described? |
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| 55478 | A truck covers 40.0 m in 8.50 s while smoothly slowing down to a final speed of 2.80 m/s.
(a) Find its original speed.
(b) Find its acceleration. |
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| 55479 | To protect his food from hungry bears, a boy scout raises his food pack with a rope that is thrown over a tree limb at height h above his hands. He walks away from the vertical rope with constant velocity vboy, holding the free end of the rope in his hands (Fig. P2.71).
(a) Show that the speed v of the food pack is given by x(x 2 + h)-1/2 vboy where x is the distance he has walked away from the vertical rope.
(b) Show that the acceleration a of the food pack is h2(x 2 + h2)-3/2 v 2 boy .
(c) What values do the acceleration a and velocity v have shortly after he leaves the point under the pack (x = 0)?
(d) What values do the pack’s velocity and acceleration approach as the distance x continues to increase? |
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| 55480 | A tile floor in a bathroom may feel uncomfortably cold to your bare feet, but a carpeted floor in an adjoining room at the same temperature will feel warm. Why? |
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| 55481 | A thermodynamic system undergoes a process in which its internal energy decreases by 500 J. At the same time, 220 J of work is done on the system. Find the energy transferred to or from it by heat. |
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| 55482 | A thermodynamic process occurs in which the entropy of a system changes by - 8.0 J/K. According to the second law of thermodynamics, what can you conclude about the entropy change of the environment? |
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