Question

The train operator must blow two blasts of the whistle in order to _____.

1) Signal the train to stop
2) Signal the train to start
3) Signal the train to slow down
4) Signal the train to change tracks

Answer 1

Two blasts of a train's whistle typically signal the train to start, which is a standardized form of communication among train operators and crew.

Step-by-step explanation:

The question pertains to the signal used by train operators when they blow their whistles, which is correlated with the physics of sound and motion. When a train operator blows two blasts of the whistle, it typically signals the train to start. This practice is standardized and used to communicate with the crew and anyone else who might need to be aware of the train's movements.

The sound of the train whistle and the frequency change observed due to the Doppler effect are relevant concepts here. If you hear the pitch of a train's horn as being lower than its actual frequency, it indicates that the train is moving away from you, or that you are moving away from it. To match the train's speed, one would need to adjust their speed accordingly but the question about whistle signals is more about communication protocol than the physics of sound.