Predicted Amplitude for Standing Waves on a String: Can It Be Calculated?

[CalcYouLater]

Homework Statement

One end of a string is attached to a vibrating "reed" that vibrates at 120 Hz. The other end is passed along a pulley stationed 1 meter away from the vibrating reed. Different masses are hung from the end of the string that passes over the pulley in order to create a restoring force given by F = m*g. The mass is adjusted to force the string into the fundamental mode and the next 3 harmonics. The linear mass density of the string is 1.35*10^-4 kg/m.

What is the expected amplitude for the fundamental mode and the next 3 harmonics?

Homework Equations

$$m_n=\frac{\mu*4*L^2*f^2}{n^2*g}$$

$$P_{avg}=\frac{1}{2}*\mu*4*\pi^2*f^3*(\lambda*A^2)$$

The Attempt at a Solution

This is for a lab report on standing waves. In this report, I am to graph the average power as a function of the quantity lambda*amplitude^2 and compare it to a theoretical average power. I don't think it is possible to find a theoretical amplitude. Am I wrong?

 

[jbsteele]

Is there a way to find the expected amplitude for the fundamental mode and the next 3 harmonics? The only equation I seem to have available is the equation for finding the mass. Is this equation useful for finding the amplitude?