A train blows its horn as it approaches a crossing. The train engineer observes a frequency of 118 Hz and a stationary observer observes a frequency of 122 Hz. What is the speed of the train? Use the speed of sound as 340m/sec

1 answer

Fo = ((Vs+Vo)/(Vs-Vt))*Ft = 122 Hz
((340+0)/(340-Vt))*118 = 122
(340/(340-Vt))*118 = 122
40,120/(340-Vt) = 122
41,480-122Vt = 40,120
-122Vt = 40,120 - 41,480 = -1360
Vt = 11.15 m/s. = Velocity of the train.