HARD physics?

[Tonia C]

A car is moving at 16.0m/s, passes an observer while the horn is pressed. Find the differences between the frequency of the sound heard when the car approaches and when it recedes from the stationary observer. The velocity of sound is 343m/s and the frequency of the sound of the car's horn is 583HZ

[M W]

you should google doppler shift...

here. I've done it for you...

http://en.wikipedia.org/wiki/Doppler_shift

let f' = observed frequency
f = emitted frequency
v = velocity sound
vc = velocity of car

f' = [(v) / (v + or - vc)] x f

it's + or - depending on if if the car is approacing you or driving away. think of race cars. cars driving away have lower frequency sound. so denominator must be larger to make fraction smaller. so away = +

so frequency coming towards you is

f' = [(343 m/s) / (343 m/s - 16.0 m/s)] x 583 hz = 611 hz

away from you is

f' = [(343 m/s) / (343 m/s + 16.0 m/s)] x 583 hz = 557 hz