Physics

Key Equations

PhysicsKey Equations

14.1Speed of Sound, Frequency, and Wavelength

 speed of sound $v=fλ v=fλ$

14.2Sound Intensity and Sound Level

 intensity $I= P A I= P A$ sound intensity $I= ( Δp ) 2 2ρ v w I= ( Δp ) 2 2ρ v w$ sound intensity level

14.3Doppler Effect and Sonic Booms

 Doppler effect observed frequency (moving source) $f obs = f s ( v w v w ± v s ) f obs = f s ( v w v w ± v s )$ Doppler effect observed frequency (moving observer) $f obs = f s ( v w ± v obs v w ) f obs = f s ( v w ± v obs v w )$

14.4Sound Interference and Resonance

 beat frequency $f B =| f 1 − f 2 | f B =| f 1 − f 2 |$ resonant frequencies of a closed-pipe resonator resonant frequencies of an open-pipe resonator