Lecture22

Physics 101: Lecture 22 Sound ,[object Object],[object Object],[object Object],[object Object],EXAM III

Speed of Sound ,[object Object],[object Object],B = bulk modulus Medium Speed (m/s) Air 343 Helium 972 Water 1500 Steel 5600

Velocity ACT ,[object Object],[object Object],[object Object],[object Object],V 1 =965m/s V 0 =343m/s correct

Frequency ACT ,[object Object],[object Object],[object Object],[object Object],Time between wave peaks does not change! f 1 f 0 correct

Wavelength ACT ,[object Object],[object Object],[object Object],[object Object], 0  1 correct  = v / f

Intensity and Loudness ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Log 10 Review ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],19 ,[object Object],[object Object]

Decibels ACT ,[object Object],[object Object],[object Object],[object Object],[object Object]

Amazing Ear (not on exam) ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Intensity ACT ,[object Object],[object Object],Area goes as d 2 so if you are ½ the distance the intensity will increase by a factor of 4 Speaker radiating power P I 1 = P/(4  D 1 2 ) D 1 I 2 = P/(4  D 2 2 ) D 2

Standing Waves in Pipes ,[object Object],[object Object],[object Object],Open at one end: Pressure AntiNode at closed end :  = 4 L / n n odd Nodes still! Nodes in pipes!

Organ Pipe Example ,[object Object],Pressure Node at each end.  = 2 L / n n=1,2,3..  = L for first harmonic (n=2) f = v /  v = f  = (382 s -1 ) (0.9 m) = 343 m/s

Resonance ACT ,[object Object],[object Object],f = v/ 

Preflight 1 ,[object Object],[object Object],Doppler Example Audio Doppler Example Visual When a source is going awaay from you then the distance between waves increases which causes the frequency to increase. thats how it happens in the movies

Doppler Effect moving source v s ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],Knowing if Vo and Vs are negative or positive.

Doppler Effect moving observer (v o ) ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],Combine: f o = f s (1-v o /v) / (1-v s /v)

Doppler ACT ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],v s f v o f’ v correct

Doppler sign convention ,[object Object],[object Object],[object Object],[object Object],+ If same direction as sound wave - If opposite direction to sound wave

Constructive interference Destructive interference Interference and Superposition

Superposition & Interference ,[object Object],[object Object],[object Object],What does C(t) = A(t) + B(t) look like?? A(  1 t) B(  2 t)

Superposition & Interference ,[object Object],[object Object],[object Object],A(  1 t) B(  2 t) C(t) = A(t) + B(t) CONSTRUCTIVE INTERFERENCE DESTRUCTIVE INTERFERENCE

Beats ,[object Object],[object Object],[object Object],where and cos(  L t)

Summary ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Lecture22

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Lecture22

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