Question

13. A burglar alarm is wailing with a frequency of 1200. hertz. What
frequency does a cop hear who is driving towards the alarm at a speed of
40.0 m/s? The air temperature is 35.0 oC.

Answer 1

Answer:

Frequency heard by the police is 1336 Hz

Explanation:

As we know that the speed of sound in air is given as

$v = 332 + 0.6 t$

now we know that

t = 35 degree C

so we have

$v = 332 + 0.6(35)$

$v = 353 m/s$

now we know that if source and observer moves relative to each other then the observed frequency by the observer is given as

$f' = f(\frac{v + v_o}{v})$

$f' = 1200(\frac{353 + 40}{353})$

$f' = 1336 Hz$