Physics: A fire truck has a 1200 Hz siren. The speed of sound in air is 343 m/s. If the fire truck travels...?

this is a problem involving the doppler effect

if the vehicle is receding, the wavelength will become longer and the frequency smaller; we can calculate this from the doppler effect equation

f(observed) = c/(c+V) x f(source)

where f(observed) is the frequency measured by the observer, c is the speed of sound, V is the speed of the vehicle, and f(source) is the frequency in the reference frame of the siren

note the plus sign in the denominator, that is the form for the source receding; if the person were moving toward the source, there would be a negative in the denominator

we have then

f(observed) = 343m/s / (343m/s + 35m/s) x 1200Hz

f(obs) = 1089Hz

they do no longer, or a minimum of maximum do no longer. they could evaluate it a waste of ammo. Why do such lots of Muslims international extensive think of firing weapons interior the air is that this way of cool element of do while celebrating the homicide with the help of terrorists of human beings?