Register to reply

Power and Amplitude of sound wave

by Trooko
Tags: amplitude, power, sound, wave
Share this thread:
Nov6-05, 12:30 AM
P: 8
For my homework,
To find Amplitude of the wave,
for a longitudinal wave travelling down a copper rod.
Given: frequency, radius of copper rod, average power, Young's constant, density, wavelength.
what equation should I consider?
I'm thinking something like P=(omega*amplitud)^2 because I know power is proportional to amplitude and frequency of the wave....but I know that's wrong.
Phys.Org News Partner Science news on
World's largest solar boat on Greek prehistoric mission
Google searches hold key to future market crashes
Mineral magic? Common mineral capable of making and breaking bonds
Nov7-05, 08:20 AM
Astronuc's Avatar
P: 21,827
The displacement amplitude A is given by:

[tex]A\,=\,\frac{\Delta{p_o}}{\omega\,\rho\,c}[/tex], where

[itex]\Delta{p_o}[/itex] is the pressure amplitude,

[itex]\omega[/itex] is the angular frequency given by [itex] 2\,\pi\,f[/itex],

[itex]\rho[/itex] is the material density, and

c = speed of sound in the material, which is given by -

[tex] c = \sqrt{\frac{E}{\rho}}[/tex]

where E is Young's (Elastic) modulus.

The intensity of the sound wave is I = P/a, where P is the power of the wave per unit transverse area, a, and

P = 1/2 [itex]\omega^2[/itex]A2[itex]\rho[/itex] c

Register to reply

Related Discussions
Equation for Sound wave power. Introductory Physics Homework 3
Amplitude of Wave Introductory Physics Homework 1
Amplitude of Sound Waves from Two Sources at a Point Introductory Physics Homework 6
Pressure amplitude/sound level Introductory Physics Homework 13
Amplitude of EM wave Introductory Physics Homework 1