 AAPT Quiz 2000 Physics Quiz Bowl (21-40)
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A car of mass m slides across a patch of ice at a speed v with its brakes locked. It then hits dry pavement and skids to a stop in a distance d. The coefficient of kinetic friction between the tires and the dry road is μ.
21. If the car had a mass of 2m, it would have skidded a distance of
22. If the car had a speed of 2v, it would have skidded a distance of
23. If all of the resistors in the following simple circuit have the same resistance, which would dissipate the greatest power? 24. Consider an object that has a mass, m, and a weight, W, at the surface of the moon. If we assume the moon has a nearly uniform density, which of the following would be closest to the object's mass and weight at a distance halfway between the Moon's center and its surface?
25. The net force on a rocket with a weight of 1.5 x 104 newtons is 2.4 x 104 newtons. About how much time is needed to increase the rocket's speed from 12 m/s to 36 m/s near the surface of the Earth at takeoff?
26. A 500-gram ball moving at 15 rn/s slows down uniformly until it stops. If the ball travels 15 meters, what was the average net force applied while it was coming to a stop?
27. The following diagram represents an electrical circuit containing two uniform resistance wires connected to a single flashlight cell. Both wires have the same length, but the thickness of wire X is twice that of wire Y. Which of the following would best represent the dependence of electric potential on position along the length of the two wires?
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An ideal elastic rubber ball is dropped from a height of about 2 meters, hits the floor and rebounds to its original height.
28. Which of the following graphs would best represent the distance above the floor versus time for the above bouncing ball?
29. Which of the following graphs would best represent acceleration versus time for the bouncing ball?
30. Monochromatic light falls on a single slit 0.01 cm wide and develops a first-order minimum (dark band) 0.59 cm from the center of the central bright band on a screen that is one meter away. Determine the wavelength of the light.
31. The average signal to noise ratio for a particular tape recorder is 50 decibels. This means that the loudness of an average reproduced signal is about how many times louder than the loudness of the tape noise?
32. A block rests on a flat plane inclined at an angle of 30º with respect to the horizontal. What is the minimum coefficient of friction necessary to keep the block from sliding?
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A natural horn (trumpet with no valves) is similar to an pipe open at both ends. A musician plans to create a fundamental frequency of 256 Hz (middle C) using the horn.
33. If sound travels at 350 m/s, what must be the length of this horn?
34. A talented musician can produce a number of overtones on this natural horn, what would be the frequency of the fourth overtone produced when the musician is playing a middle C fundamental?
35. A 100 g block of aluminum at 90ºC is brought into contact with a 100 g block of lead at 10ºC inside a thermally isolated container. The final temperature of the system at equilibrium would be closest to
36. A hall is thrown vertically upward with an initial velocity v and an initial kinetic energy Ek. When the hall is half way to the top of its flight, it has a velocity of ___ and a kinetic energy of ___?
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During a recent winter storm, bales of hay had to be dropped from an airplane to a herd of cattle below. Assume the airplane flew horizontally at an altitude of 180 m with a constant velocity of 50 m/s and dropped one hail of hay every two seconds. It is reasonable to assume that air resistance will be negligible for this situation.
37. As the bales are falling through the air, what will happen to their distance of separation?

38. About how far apart from each other will the hales land on the ground?
39. If a boat can travel with a speed of v in still water, which of the following trips will take the least amount of time?

40. Suppose two cars are racing on a circular track one kilometer in circumference. The first car can circle the track in 15 seconds at top speed while the second car can circle the track in 12 seconds at top speed. How much lead does the first car need starting the last lap of the race not to lose?