Shock, Bow, Doppler, Beats Recap

Tacoma Narrows Bridge

Bridge collapsed due to wind-induced resonance.

Resonance

Natural frequency matches external frequency, causing oscillations.

Natural Frequency

Frequency at which a system oscillates without external force.

Structural Failure

Collapse of a structure due to excessive stress or forces.

Wave Interference

Overlap of waves creating new wave patterns.

Constructive Interference

Crests align, forming a larger resultant wave.

Destructive Interference

Crest meets trough, canceling waves or reducing amplitude.

Beats

Fluctuating sound intensity from two waves of different frequencies.

Standing Waves

Waves traveling in opposite directions create fixed nodes.

Nodes

Points of no displacement in standing waves.

Antinodes

Points of maximum displacement in standing waves.

Open-End Air Columns

Tubes open at both ends for sound wave resonance.

First Harmonic

Fundamental frequency corresponding to half the wavelength.

Closed-End Air Columns

Tubes closed at one end, resonating at quarter wavelengths.

Doppler Effect

Frequency change due to the relative motion of source and observer.

Shock Waves

Created when an object exceeds the speed of sound.

Doppler Ultrasound

Measures blood flow using frequency shifts of sound waves.

Radar

Measures speed of objects using reflected radio waves.

Sonar

Underwater navigation using sound pulses and reflections.

Redshift

Light shifts to longer wavelengths, indicating objects moving away.

Blueshift

Light shifts to shorter wavelengths, indicating objects moving closer.

Frequency Formula (Open Column)

f = v / (2L) for first harmonic.

Frequency Formula (Closed Column)

f = v / (4L) for first harmonic.

Applications of Sound Waves

Used in medical imaging, speed detection, and navigation.

When a sound wave hits an air molecule, it

moves the air molecule back and forth

On the displacement vs time graph, when the wave plotted hits the x axis (the time line), the air molecule

is back at it's original position

On the displacement vs time graph, when the wave plotted is below the x axis, the air molecule

is moved backward from it's original position

If two tones with the same frequency are produced at the same position, this is called

constructive interference

If two tones with the same frequency are produced but are placed at a halfway distance of the wavelength, this is called

destructive interference

If two tones with the same frequency are produced but are placed at a halfway distance of the wavelength, the tone produced at 3 meters.

will be silent or softer

If two tones with the same frequency are produced at the same distance, the tone produced at 3 meters.

will be louder

If two tones with different frequencies are produced at the same distance, the tone produced at 3 meters.

will have wobbles

The phenomena if two tones with different frequencies are produced at the same distance is called .

beat frequency

If one tone of 458 Hz is played against a 449 Hz tone, how much distance between constructive interference peaks would there be?

9Hz

If one tone of 495 Hz is played against a 512 Hz tone, how many wobbles per second would there be?

17

If a saxophonist was playing an "A" note perfectly in tune (as they normally do) at 440 Hz and a trumpet was playing the same note but they measured 15 beats in their combined sound, what could be the trumpets frequency?

425Hz