# Accoustic problem

1. May 7, 2006

### Werg22

The human tympanum is displaced by sound waves. This displacement is linked to the acting force by the equation:

F = 4x

where x is the displacement in meters.

A wave of frequency 1000 Hz provoques a displacement of 1.5 x 10^-5 m. Prove that the energy given to the tympanum is given in 0.25*10^-3 s. Also find the average power of the wave.

I don't how power is linked to frequency and energy in therms of waves...

Last edited: May 7, 2006
2. May 8, 2006

### andrevdh

The intensity of a wave is defined as
$$I=\frac{P}{S}$$
where $P$ is its power (the amount of energy it transports per second) through a (perpendicular) cross sectional area $S$.

The intensity is given by
$$I=2\pi^2v\rho f^2A^2$$
which includes the propagation speed of the wave, $v$, while it is travelling throught a medium of density $\rho$, creating a disturbance with a frequency $f$ and amplitude $A$.

Last edited: May 8, 2006