Question

Two trains on separate tracks move toward each other. Train 1 has a speed of 109 km/h; train 2, a speed of 99.0 km/h. Train 2 blows its horn, emitting a frequency of 500 Hz. What is the frequency heard by the engineer on train 1?

Answer 1

Answer:

$f_o=592.36 Hz$

Explanation:

Given that

Train 1 (observer):

Speed = 109 km/h

Train 2 (source):

Speed = 99 km/h

Train 2 emitting frequency = 500 Hz

We know that observer and source are moving toward each other, then frequency heard by observer can be given as follows

$f_o=\left(\dfrac{C+V_o}{C-V_s}\right)f_s$

Where C is the velocity of sound  (C=1225 Km/h)

Now by putting the values

$f_o=\left(\dfrac{C+V_o}{C-V_s}\right)f_s$

$f_o=\left(\dfrac{1225+109}{1225-99}\right)\times 500$

$f_o=592.36 Hz$