Questions from College Physics


Q: A train sounds its horn as it approaches an intersection. The

A train sounds its horn as it approaches an intersection. The horn can just be heard at a level of 50. dB by an observer 10 km away. (a) What is the average power generated by the horn? (b) What inten...

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Q: An outside loudspeaker (considered a small source) emits sound waves

An outside loudspeaker (considered a small source) emits sound waves with a power output of 100 W. (a) Find the intensity 10.0 m from the source. (b) Find the intensity level in decibels at that dista...

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Q: Show that the difference in decibel levels β1 and β 2 of

Show that the difference in decibel levels β1 and β 2 of a sound source is related to the ratio of its distances r1 and r2 from the receivers by the formula

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Q: A skyrocket explodes 100 m above the ground (Fig. P14

A skyrocket explodes 100 m above the ground (Fig. P14.24). Three observers are spaced 100 m apart, with the first (A) directly under the explosion. (a) What is the ratio of the sound intensity heard b...

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Q: A baseball hits a car, breaking its window and triggering its

A baseball hits a car, breaking its window and triggering its alarm which sounds at a frequency of 1250 Hz. What frequency is heard by a boy on a bicycle riding away from the car at 6.50 m/s?

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Q: A train is moving past a crossing where cars are waiting for

A train is moving past a crossing where cars are waiting for it to pass. While waiting, the driver of the lead car becomes sleepy and rests his head on the steering wheel, unintentionally activating t...

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Q: A commuter train passes a passenger platform at a constant speed of

A commuter train passes a passenger platform at a constant speed of 40.0 m/s. The train horn is sounded at its characteristic frequency of 320. Hz. (a) What overall change in frequency is detected by...

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Q: An airplane traveling at half the speed of sound emits a sound

An airplane traveling at half the speed of sound emits a sound of frequency 5.00 kHz. At what frequency does a stationary listener hear the sound (a) As the plane approaches? (b) After it passes?

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Q: Two trains on separate tracks move toward each other. Train 1

Two trains on separate tracks move toward each other. Train 1 has a speed of 1.30 x 102 km/h; train 2, a speed of 90.0 km/h. Train 2 blows its horn, emitting a frequency of 5.00 x 102 Hz. What is the...

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Q: On a hot summer day, the temperature of air in Arizona

On a hot summer day, the temperature of air in Arizona reaches 114°F. What is the speed of sound in air at this temperature?

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