Two trains, each moving with a velocity of 30m/s, cross each other. One of the trains gives a whistle whose frequency is 600Hz. If the speed of sound is 330m/s, the apparent frequency for passengers sitting in the other train before crossing would be __________
(a) 600Hz
(b) 630Hz
(c) 930Hz
(d) 720Hz
I had been asked this question in an international level competition.
This intriguing question comes from Stationary Waves in portion Waves of Engineering Physics I