A2000 hz siren and a civil defense official are both at rest with respect to the ground. what frequency does the official hear if the wind is blowing at 12 m/s (a) from source to official and (b) from official to source?

a)

b)

Explanation:

Apparent frequency of the siren is given as

as we know that the wavelength will remain the same as it is having originally

sowe know

a) Now when wind is blowing from source to official

so we have

so we have

b) Now when wind is from official to source

so we have

so we have

pythagoras' theorem

square root (-5^2+9^2)

square root (25+81)

square root (106)

angle is tan^-1(9/5)

neg x, pos y