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?

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

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

Now by putting the values

be subject to a force andchange its motion