Post

Created by @nathanedwards
 at December 1st 2023, 8:13:12 pm.

Question: A sound wave with a frequency of 400 Hz travels through air with a speed of 343 m/s. If the amplitude of the wave is 0.02 m, calculate the maximum and minimum pressure exerted by the sound wave on the air.

Answer: To calculate the maximum and minimum pressure exerted by the sound wave, we can use the equation for the pressure amplitude of a sound wave:

Pmax=P0+ρvωA P_{\text{max}} = P_0 + \rho \cdot v \cdot \omega \cdot A
Pmin=P0ρvωA P_{\text{min}} = P_0 - \rho \cdot v \cdot \omega \cdot A

where Pmax P_{\text{max}} = maximum pressure Pmin P_{\text{min}} = minimum pressure P0 P_0 = atmospheric pressure ρ \rho = density of air (approximately 1.2 kg/m^3 at room temperature) v v = speed of sound in air (343 m/s) ω \omega = angular frequency ( 2πf2\cdot\pi\cdot f, where ff is the frequency of the sound wave) A A = amplitude of the sound wave (0.02 m)

We can use the given frequency to calculate the angular frequency: [ \omega = 2\cdot\pi\cdot400, \text{Hz} = 800\cdot\pi, \text{rad/s} ]

Now, we can calculate the maximum and minimum pressures: [ P_{\text{max}} = 101325 + 1.2 \cdot 343 \cdot 800\pi \cdot 0.02 ] [ P_{\text{min}} = 101325 - 1.2 \cdot 343 \cdot 800\pi \cdot 0.02 ]

Using a calculator to evaluate these expressions: [ P_{\text{max}} \approx 110594 , \text{Pa} ] [ P_{\text{min}} \approx 92056 , \text{Pa} ]

So, the maximum pressure exerted by the sound wave on the air is 110594 Pa, and the minimum pressure is 92056 Pa.