Question

An
 approaching 
train
 produces 
the 
RP1
signal
(attention 
signal) 
at
 600 Hz .
The 
train
 moves 
with
 the
speed
 of
 120 km/h. What
 is
 the
 frequency and
 the
wavelength
 of 
the 
sound

detected 
by 
a 
person
 standing
 next 
to 
the
 track?


Answer 1

Vt=120000m/h = 120000m/3600s = 33.33 m/s

Fp = ((Vs+Vp)/(Vs-Vt))*Ft
Fp = ((343+0)/(343-33.33))*600 Hz
Fp = (343/309.7)*600 = 664.6 Hz = Freq.
heard by the person.

L = Vs/Fp = 343/664.6 = 0.516 m. = Wave-
length.