Which situations might cause two observers (A and B) to measure different frequencies for the same vibrating object? Select the two correct answers. (2 points)
Responses
Observer A is stationary and Observer B is moving.
Observer A and Observer B are both stationary and at the same distance from the object.
Observer A and Observer B are moving at different speeds relative to each other.
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.
The correct answers are:
1. Observer A is stationary and Observer B is moving.
3. Observer A and Observer B are moving at different speeds relative to each other.
The correct answers are:
1. Observer A is stationary and Observer B is moving.
2. Observer A and Observer B are moving at different speeds relative to each other.
To understand why these situations can cause two observers to measure different frequencies for the same vibrating object, we need to consider the concept of the Doppler effect.
The Doppler effect is the change in frequency or wavelength of a wave, such as sound or light, in relation to an observer's motion. It occurs when there is relative motion between the source of the wave and the observer.
In the first situation, if Observer B is moving towards the vibrating object, they will experience a higher frequency than Observer A, who is stationary. This is because the motion of Observer B compresses the wavefronts, causing the wavelength to decrease and the frequency to increase.
In the second situation, if Observer A and Observer B are moving at different speeds relative to each other, the relative motion between them and the vibrating object will cause them to measure different frequencies. This is because both observers are moving with respect to the object, and their different velocities will result in different Doppler shifts.
In the other two options, the observers either have the same distance or are at different distances from the vibrating object, but they are either both stationary or moving at the same velocity. In these cases, the relative motion between the observers and the object is not present, so there will be no Doppler effect, and therefore the frequencies measured by both observers will be the same.