3. An observer is standing next to the tracks, watching a train approach. The train travels at 30 m/s and blows its whistle at 8,000 Hz as it approache
by the observer without slowing down. Assuming the speed of sound is 340 m/s, how much of a frequency change did the observer hear?
A. 1,412 Hz
B. 1,423 Hz
C. 1,485 Hz
D. 1,551 Hz

Aloop of wire is in a magnetic field such that its axis is parallel with the field direction. which of the following would result in an induced emf in the loop? choose all that apply. a loop of wire is in a magnetic field such that its axis is parallel with the field direction. which of the following would result in an induced emf in the loop? choose all that apply. moving the loop outside of the magnetic field region. spin the loop such that its axis does not consistently line up with the magnetic field direction. change the magnitude of the magnetic field. change the diameter of the loop