which situations might cause 2 observers (a and b) to measure different frequencies for the same vibrating object? select the two correct answers.
observer A and observer B are both stationary and at the same distance from the 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 an B are stationary but at different distances from the vibrating object
The two correct answers are:
1. Observer A is stationary and observer B is moving.
2. Observer A and Observer B are stationary but at different distances from the vibrating object.
The two correct answers are:
1. Observer A is stationary and observer B is moving: When observer B is moving towards or away from the vibrating object, it results in a change in the frequency perceived by observer B due to the Doppler effect.
2. Observer A and Observer B are moving at different speeds relative to each other: When both observers are in motion and have different velocities relative to each other and the vibrating object, the relative motion causes a change in the perceived frequency for each observer. This is also due to the Doppler effect.
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 observers A and B to measure different frequencies for the same vibrating object, let's consider the concept of the Doppler effect.
The Doppler effect is a phenomenon that occurs when there is relative motion between the source of a wave (in this case, the vibrating object) and the observer. It causes a change in the observed frequency of the wave.
In the first situation, if observer A is stationary and observer B is moving towards or away from the vibrating object, the frequency of the waves reaching each observer will be different. As observer B moves towards the object, the waves will be compressed, resulting in an increase in frequency. Conversely, as observer B moves away from the object, the waves will be stretched, resulting in a decrease in frequency. Therefore, observer A and B will measure different frequencies.
In the second situation, when both observer A and B are moving at different speeds relative to each other, the relative velocity between the observers also affects the observed frequency. If observer A is moving towards observer B, the apparent frequency will be higher than that measured by observer A alone. Conversely, if observer A is moving away from observer B, the apparent frequency will be lower. As a result, observer A and B will again measure different frequencies.
It is important to note that in the other two situations (where both observers are stationary and at the same distance, or when they are stationary but at different distances from the object), there won't be any relative motion between the observers and the vibrating object. Therefore, they will measure the same frequency.