- #1
Soren4
- 128
- 2
Homework Statement
A source emits a spherical sound wave at frequency ##f=110Hz## with power ##P=1 W## in a solid angle of ##2 \pi sr##. An observer moves with velocity ##v_{oss}=108 km/h## towards the source. Determine the sound intensity level received by the moving observer.
Homework Equations
Doppler effect and sound intensity level
The Attempt at a Solution
I just do not know how to approach the problem because it is very different from a common Doppler effect problem.
The frequency perceived by the observer is ##f'=f(\frac{c+v_{oss}}{c})## but this does not give me the sound intensity level
To find the sound intensity level means to find the intensity. Now, the intensity of a sound wave is ##I= 2 \pi^2 f^2 A^2 \rho##.
Plugging ##f'## in the formula for ##I## does not give the correct result and there must be something that I am missing. How to do such exercises?