The figure shows wavefronts from a buzzer moving steadily to the right. Observer P is ahead of the buzzer, and observer Q is behind it. Compared with the emitted frequency, what does each receive?

Use the moving-source wavefront figure. How do the wavelengths received by observers P and Q compare?

The figure shows wavefronts from a moving siren, with observers P and Q on opposite sides. Which observer hears the higher pitch?

In the wavefront diagram, a whistle moves to the right at constant speed. P stands in front of the whistle and Q stands behind it. Which statement describes the periods they observe?

The figure shows a source moving right through still air. P is ahead of it and Q is behind it. Which comparison of observed frequency is correct?

A cart carries a speaker to the right while emitting a steady tone. In the wavefront figure, P is in front of the cart and Q is behind it. What is true about the sound speed in the air?

Look at the moving-source wavefront diagram. Which observer, P or Q, receives the lower frequency?

In the diagram, a horn moves right while emitting a constant frequency. P is ahead on the right, and Q is behind on the left. Which statement best matches the wavefront spacing?

A moving buzzer's wavefronts are drawn around successive source positions. P is in front of the moving buzzer and Q is behind it. What does Q hear compared with P?

In the figure, a sound source moves right at constant speed. P stands ahead and Q behind. If the source emits 600 Hz, which qualitative result is correct?

A fire truck siren emits a steady 700 Hz tone while the truck drives directly toward a stationary listener at constant speed. What does the listener hear while the truck approaches?

A train horn emits a constant 300 Hz tone as the train moves directly away from a stationary student. Which description of the observed sound is correct?

A runner moves straight toward a stationary loudspeaker that emits a steady 500 Hz tone in still air. Which sound does the runner hear?

A skateboarder rolls straight away from a stationary speaker playing a steady 440 Hz tone. What happens to the frequency the skateboarder observes?

A police car with a steady siren is parked, and a cyclist rides directly toward it at constant speed. Which explanation correctly predicts the cyclist's pitch?

A whistle on a cart moves directly away from a stationary listener while emitting a steady tone. Which statement is correct?

A listener walks directly away from a stationary tuning fork vibrating at a steady 256 Hz. What frequency comparison is correct?

A drone carries a buzzer straight toward a motionless observer while the buzzer emits a constant 900 Hz tone. Which option describes the Doppler shift?

A student stands still while an alarm clock on a rolling cart moves directly past and away at constant speed after passing. What happens to the observed frequency after it has passed?

A kayaker paddles straight toward a stationary foghorn that emits a steady tone. Which statement correctly separates the observer effect from a source effect?

A loudspeaker at rest in still air sounds a steady tone, and a cyclist rides at constant speed straight toward it. Which quantity is the same for the cyclist as for a person standing still at that place?

A siren source moves through still air toward a stationary observer while emitting a constant tone. Which quantity is not changed by the source's motion?

A stationary buzzer emits a steady tone, and a jogger moves directly away from it. Which quantity in the air stays the same as it would be if the jogger stopped?

A whistle moves away from a stationary listener through still air. Which quantity remains the same as when the whistle was at rest in the same air?

A passenger on a train moves toward a stationary horn in still air. Compared with a person standing still nearby, which quantity is larger for the passenger?

A sound source moves steadily through still air while emitting a constant tone. Why are the wavefronts closer together ahead of the source?

An ambulance siren emits 660 Hz and approaches a stationary observer at 30.0 m/s. The speed of sound is 340 m/s. For an approaching source, f' = f × v/(v − vs). What frequency is heard?

A train horn emits 500 Hz as the train moves away from a stationary observer at 20.0 m/s. The speed of sound is 340 m/s. For a receding source, f' = f × v/(v + vs). What frequency is heard?

A stationary speaker emits 440 Hz, and an observer runs toward it at 15.0 m/s. The speed of sound is 340 m/s. For an approaching observer, f' = f × (v + vo)/v. What frequency is heard?

A stationary alarm emits 1000 Hz while an observer moves directly away at 25.0 m/s. The speed of sound is 340 m/s. For a receding observer, f' = f × (v − vo)/v. What frequency is heard?