Editorial - Fisika - Gelombang Bunyi

Rumus

v=ƒ⋅λ

(L_n)=(2*n-1)/4*λ

That's if the tube starts at an open into a closed pipe.

Open is always at peaks, while closed is at intersections.

(ƒ_p)=(v±(v_p))/(v∓(v_s))⋅(ƒ_s)

• v is speed of the wave

• ƒ is frequency

• λ is wavelength

• (ƒ_p) is frequency after doppler effect

• v is speed of the wave, ususally 340

• (v_p) is the speed of the subject

• (v_s) is the speed of the source of the wave

I=P/(4*π*r2)

• I is intensity of the sound

• P is power

• r is the distance

TI=10*(log_10)(I/(I_0))

(TI_n)=TI+10*(log_10)(n)

(TI_2)=(TI_1)+20*(log_10)((r_1)/(r_2))

Problem 1

Subproblem 1.1

340=680*λ

λ=0.5=50

True

Subproblem 1.2

L=1/4⋅50=12.5

False

Subproblem 1.3

True

Problem 2

True False True

Problem 3

Subproblem 3.1

ƒ=335/(335-5)⋅670>670

True

Subproblem 3.2

ƒ=(335-5)/335⋅670=660

True

Subproblem 3.3

ƒ=(335+5)/335⋅670=680

True

Problem 4

Subproblem 4.1

ƒ=(340-15)/(340-20)⋅640=650≠680

False

Subproblem 4.2

ƒ=(340+15)/(340+20)⋅640=631≠630

True it's close enough

Subproblem 4.3

Clearly false

Problem 5

Subproblem 5.1

(360*π)/(4*π*302):(360*π)/(4*π*402)

1/900:1/1600

1/9:1/16

False

Subproblem 5.2

I=(360*π)/(4*π⋅900)=1/10=0.1

True

Subproblem 5.3

TI=10*(log_10)((10(-1))/(10(-12)))=110

True

Problem 6

Subproblem 6.1

TI=50+10*(log_10)(100)=70

Already true because this is the dB at the start

Subproblem 6.2

s=1.25⋅36=45+5=50

TI=70+20*(log_10)(5/50)=70+20⋅(-1)=50

False

Subproblem 6.3

False?