Question

which situations might cause two observers (a and b) to measure different frequencies for the same vibrating object? select the two correct answers. (1 point) observer a and observer b are stationary but at different distances from the vibrating object. observer a is stationary and observer b is moving. observer a and observer b are moving at different speeds relative to each other. observer a and observer b are both stationary and at the same distance from the object.

Explanation:

The Doppler effect explains that the frequency of a wave (like sound from a vibrating object) perceived by an observer changes if there is relative motion between the source and the observer.

• For "Observer A is stationary and Observer B is moving": The motion of B relative to the source (or A) will cause a Doppler shift, so their measured frequencies can differ.
• For "Observer A and Observer B are moving at different speeds relative to each other": Different relative speeds mean different relative motions with respect to the source, leading to different perceived frequencies.
• "Observer A and Observer B are stationary but at different distances from the vibrating object": Distance alone (without motion) doesn't change the frequency (though it affects intensity), so this is incorrect.
• "Observer A and Observer B are both stationary and at the same distance from the object": No relative motion or distance difference affecting frequency, so same frequency, incorrect.

Answer:

B. Observer A is stationary and Observer B is moving, C. Observer A and Observer B are moving at different speeds relative to each other