physics

[710Samantha]

The fire engine approaches a stationary car at 20 m/s. What frequency does a person in the car hear?

[rojash]

That will depend on the frequency of the fire engine's siren, which you haven't stated

[beso]

Depends on which station their car radio is tuned in to.

[beso]

Ok. Jokes aside.

Sound at sea level travels at aproximately 330 metres per second.

The perceived frequency will be increased to 350/330 times the frequency emitted by the siren.

[factor-fiction]

You just need to look up 'Doppler effect' in your notes/ text book/ reliable web site.

[mibn2cweus]

beso, Try dividing the sound velocity by the difference rather than dividing the sum by the sound velocity and check your answer here.

[beso]

Interesting. My calculation is correct for the car moving but a little low for the source moving. It had never occurred to me that the result would be different.

Thanks for the link mib2cweus.

[mibn2cweus]

~ ~ ~ ♪ the answer ♫ is blowin' ♫ in the wind ♪ ~ ~ ~