The Longitudinal Displacement of a Mass Element in a Medium

question 3

Multiple Choice

The longitudinal displacement of a mass element in a medium as a sound wave passes through it is given by s = s_m cos (kx - ωt) .Consider a sound wave of frequency 440 Hz and wavelength 0.75m.If s_m = 12 µm, what is the displacement of an element of air located at x = 1.2 m at time t = 0.11 s?

• A)3.7 µm
• B)4.9 µm
• C)6.0 µm
• D)8.2 µm
• E)12 µm

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