Doppler effect of approaching train · CAP 2006 #16
Physics
Problem
You stand on a platform at a train station and listen to a train horn as the train approaches the station at a constant velocity. While the train approaches, but before it arrives, you hear:
(a) the intensity and the frequency of the sound both increasing;
(b) the intensity and the frequency of the sound both decreasing;
(c) the intensity increasing and the frequency decreasing;
(d) the intensity decreasing and the frequency increasing;
(e) the intensity increasing and the frequency remaining the same;