The change in pitch of a train's horn as it passes while you are standing still can be explained by
a. sympathetic vibration.
b. ultrasonic vibrations.
c. resonance.
d. the Doppler effect.

Respuesta :

AL2006

The change in pitch of a train's horn as it passes while you are
standing still can be described by the Doppler effect, but that
doesn't explain it.