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prisoha [69]
3 years ago
6

Please help.

Physics
1 answer:
cestrela7 [59]3 years ago
3 0
Hello,

<span>A police car parked on the side of the highway emits a 1200 Hz sound that bounces off a vehicle farther down the highway and returns with a frequency of 1250 Hz. 

How fast is the vehicle going?

Doppler equation formula: </span>ƒL = ƒS(v - vL)/(v - vS)

The wave returns with a frequency of 1250 Hz, the <span>echo frequency is higher; the car must be traveling towards the police car. 

</span><span>The wave echo is coming back towards the police car at the same speed as the sound wave travels towards the moving car so t</span><span>he relative speed between the cars is half of the speed of the echo.

* </span><span>speed of sound equals about 337 m/s </span>

2v / 337 = (1250/1200) - 1 
<span>2v = 14.04 m/s </span>
<span>v = 7.02 m/s
</span>
Thus, the vehicle is going 7.02 m/s.

Faith xoxo

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