document.write( "Question 1181800: Could you please show me the steps how to solve this problem?
\n" ); document.write( "The Doppler effect causes a sound moving towards you to sound higher pitched and a sound moving away from you to sound lower pitched, like observed in listening to the car horn in the video.\r
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\n" ); document.write( "f= c/(c+v)f0
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\n" ); document.write( "f is the observed frequency (pitch) of the sound, in Hertz
\n" ); document.write( "c is the speed of sound, about 761 miles per hour,
\n" ); document.write( "v is the speed of the sound source, in this case the car, in miles per hour
\n" ); document.write( "f0 is the frequency of the sound when stationary\r
\n" ); document.write( "\n" ); document.write( "Using a spectrum analyzer, we could determine the observed frequency when the car was driving away was 239 Hz and the stationary frequency was 256 Hz.\r
\n" ); document.write( "\n" ); document.write( "Use this information and the equation to estimate the speed of the car in miles/hour, to 1 decimal place.
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Algebra.Com's Answer #811715 by ikleyn(52805)\"\" \"About 
You can put this solution on YOUR website!
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document.write( "All we need to do is to substitute the given frequencies into equation\r\n" );
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document.write( "    239 = \"256%2A%28761%2F%28761+%2B+v%29%29\".\r\n" );
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document.write( "To solve it, cross multiply, simplify and find v\r\n" );
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document.write( "    239(761 + v) = 256*761\r\n" );
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document.write( "    761 + v = \"%28256%2A761%29%2F239\" = 815.1 mph\r\n" );
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document.write( "          v                       = 815.1 - 761 = 54.1 mph.\r\n" );
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document.write( "ANSWER.  The speed of the car is 54.1 miles per hour  (rounded as requested).\r\n" );
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\n" ); document.write( "\n" ); document.write( "Solved.\r
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\n" ); document.write( "\n" ); document.write( "This problem (its TWIN version) was just solved once at this forum under the link\r
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\n" ); document.write( "\n" ); document.write( "https://www.algebra.com/algebra/homework/equations/Equations.faq.question.1181384.html\r
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