which situations might cause 2 observers (a and b) to measure different frequencies for the same vibrating object? select the two correct answers.

Question

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

Answer 1

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.