Question

As the train in the image moves to the right how does the train horn sound to person a?

Answer 1

Answer:

D. The pitch does not change.

Explanation:

When the source of sound moves away, the pitch drops. and when the source of sound approaches the pitch rises. This is called'Doppler effect'.

Here the person a and the sound horn are both in the same vehicle. Which means their relative velocity is zero. So the horn is neither approaching nor receding the person A

If  the source is approaching

$f_{new}= \frac{v_{sound} }{v_{sound} -v_{source} }f_{original}$

If the source is receding

$f_{new}= \frac{v_{sound} }{v_{sound} +v_{source} }f_{original}$

Hence the right answer is option D. The pitch does not change

Answer 2

Answer:

Explanation:

Person A's velocity relative to the train is 0.  Therefore, the pitch of the horn will not change.